Coherence at Last? Transatlantic Cooperation in Response to the Geostrategic Challenge of China

In light of the larger contextual picture of increased geostrategic rivalry with China, this article focuses on the question whether transatlantic cooperation responses towards the geostrategic challenge of China can possibly be coherent at all. How can we explain coherent actions (or lack thereof) between actors across the Atlantic in their foreign policy towards China? The central idea then is to explain transatlantic cooperation responses to the geostrategic challenge of China from a coherence angle, providing us with a perspective by which we can understand why actors on both sides of the Atlantic invest in policy coherence, or rather not. We argue that this coherence angle on transatlantic relations is particularly promising as it combines a focus on actors and structural dimensions that is able to offer explanations by whom, where, and why policy coherence is achieved. By looking into two different cases, the so‐called concerted sanctions case and the AUKUS case, we find both, transatlantic coherence and incoherence, respectively, in response to the strategic challenge of China. Overall, this article has important policy implications, as it can point to the underlying factors in transatlantic policy‐making that push or obstruct coherence.


Introduction
After years of contestation and polarization, transatlantic relations may be severely weakened (Riddervold & Newsome, 2022). In an attempt to assess the weakening or strengthening of transatlantic relations, we will zoom in on one specific aspect of transatlantic relations that has recently given way to policy-making on both sides of the Atlantic: the rise of China as a contesting power of the liberal international order (LIO), its fundamental values and ideas. We are thus interested in how we can explain transatlantic cooperation in light of the geostrategic rivalry with China, more specifically whether transat-lantic cooperation responses towards the geostrategic challenge of China can possibly be coherent. How can we explain coherent actions (or lack thereof) between actors across the Atlantic in their foreign policy towards China? To answer this research question, we propose a coherence framework within which we can assess the coherence/incoherence of transatlantic actors on the basis of realist and constructivist theoretical accounts (for another realist account of transatlantic cooperation see also Olsen, 2022).
Although not usually achieved in practice, transatlantic relations should rest on policy coherence, as coherence ideally contributes, at least from a governance point of view, to efficient and effective policy outcomes (Duke & Vanhoonacker, 2006). At a minimum, coherence is the absence of inconsistencies, at a maximum the creation of policy synergy in transatlantic relations (see Marangoni & Raube, 2014;Portela & Raube, 2012). The more the policy coherence of transatlantic actors decreases, the more transatlantic policies tend to become inconsistent and miss the opportunity of policy synergies. And indeed, over the last couple of years and especially during the Trump administration, transatlantic relations suffered from a lack of US-American leadership and invested in the active contestation of multilateral cooperation (Anderson, 2018;Drozdiak, 2017, pp. 254-255). Nevertheless, as Riddervold and Newsome (2021, p. 606) argue following Ikenberry: "[T]he transatlantic relationship will withstand today's crises, including the one caused by Trump's policies, due to everyone's interest." In other words, with a new US-American leadership under President Biden it could well be that, after years of transatlantic inconsistencies and missed opportunities of synergetic policies, transatlantic actors would tend to thrive towards transatlantic policy coherence. In the context of transatlantic relations after Trump, this may imply that actors communicate and coordinate their strategic perspectives and actions in the effort to arrive at consistent and synergetic policies.
Building on coherence as discussed in European integration literature (Christiansen, 2001;Duke, 2011;Hillion, 2008;Keukeleire & Raube, 2013;Marangoni & Raube, 2014;Portela, 2021;Portela & Raube, 2012), the overall idea is to explain the drive of transatlantic actors to arrive at transatlantic coherence by using realist and constructivist theories. In other words, once we have shown whether transatlantic actors' actions were coherent or not, we use the realist and constructivist theories to explain why. By using (a) the so-called concerted sanctions case in March 2021 and (b) the so-called AUKUS case in the second half of 2021, we can point to different policy outcomes of transatlantic responses towards China, and explain them accordingly. Both cases are not only timely and recent examples of coherence and incoherence in transatlantic relations, they are also situated in the context of the new US-administration under President Biden, whose aim was to strengthen transatlantic ties-promising a greater focus on co-ordinated transatlantic relations and policy coherence after four rather confrontational years. Respectively, the policy implications of this article are interesting, as they will enable us to point to the underlying factors in transatlantic cooperation that push or obstruct coherence.

Coherence in Transatlantic Relations-How So?
From a governance perspective, coherence contributes to efficient and effective policy outcomes (Duke & Vanhoonacker, 2006). At a minimum, coherence is the absence of inconsistencies, at a maximum the creation of policy synergy in transatlantic relations (see Marangoni & Raube, 2014;Portela & Raube, 2012). Coherence can thus be understood as the opposite of an inherent contradiction or, more specifically, the opposite of contradictory policies, including strategic mismatches and policy instruments (Krenzler & Schneider, 1997, p. 134;Marangoni & Raube, 2014). In this reading of coherence, various political strategies, policies, political actors, and organisations have to think not only how to avoid incoherence, but to push for policy congruence, complementarity, and added-value (Hillion, 2008, p. 17; see also Duke, 2011). Coherence is then essentially goal-oriented and attributed of an action characterised not only by the absence of contradictions, but by synergies in pursuit of a single objective (Krenzler & Schneider, 1997, p. 134;Missiroli, 2001, p. 4).
Following Riddervold and Newsome (2021), transatlantic relations are "the overall set of relations between the European Union and the US, within the broader framework of the institutional and other connections maintained via NATO and other institutions" (p. 603). For the purpose of this article, however, we understand transatlantic actors to consist of not only the EU and the US, but also Canada, UK, and individual EU member states. For Ikenberry (2008), the transatlantic relationship is based on four key pillars: "U.S. hegemony, mutual interests, political bargains, and agreed-upon rules and norms" (as cited in Riddervold & Newsome, 2021, p. 606). But how does coherence come into play here? In fact, as Marangoni and Raube (2014) remind us, "coherence is not specific to EU external action but a buzzword in any polity" (p. 474). We may in fact use the coherence framework not only for polities, such as the EU (Portela & Raube, 2012), but also for the more loosely coupled pluralistic security community of transatlantic relations (see Adler & Barnett, 1998; see also Deutsch et al., 1957). And while one may argue that transatlantic relations have always been made of disagreement and that they have never been entirely coherent (Drozdiak, 2005), we also find evidence for cooperation and working-together (Risse, 2016). In this latter regard, coherence becomes an objective of multilateral transatlantic cooperation and reminds actors of necessary "habits of cooperation" (Smith, 2022) not the least because, from a governance perspective, coherence contributes to efficient and effective policy outcomes (Duke & Vanhoonacker, 2006;Marangoni & Raube, 2014). In this respect, it does not surprise that NATO partners underline their commitment to "a continued coherent international approach, in particular between NATO and the European Union (EU)" (NATO, 2016, para. 22) and "to contribute to the coherence and complementarity" of NATO and the EU (NATO, 2021b, para. 65).

Horizontal and Vertical Coherence-In Transatlantic Relations, Too?
As European Integration literature has shown, policy coherence can occur horizontally between organizations, and vertically between different levels of governance, for example between organisations and their member states. In the EU, horizontal coherence has often been seen as a contribution to the effective policy-making, ruling out inconsistencies across institutional actors, while vertical coherence has only then been achieved if the EU and its member states were able to establish consistencies and even policy synergies in decision-making and implementation (Christiansen, 2001;Marangoni & Raube, 2014).
In the case of transatlantic relations, we may first understand horizontal coherence as the absence of inconsistency between transatlantic actors. For example, we would expect that both the EU and NATO or, respectively, EU member states and the US do not contradict each other's policies, or even thrive towards addedvalue and synergies in their foreign policies (Marangoni & Raube, 2014). Relatedly, this conceptualization of horizontal coherence suggests that transatlantic actors and organisations may well focus on specific goal-oriented coherence, pulling their forces and ambitions to (a) avoid inconsistencies and (b) provide added-value (see Table 1). Secondly, we may understand vertical coherence as the absence of inconsistency between transatlantic organisations and member states. In a transatlantic context, we would expect that member states "walk the line" of transatlantic strategy and policy-making in NATO and, accordingly, arrive at non-contradiction and even synergies (see Table 1).
With Risse (2016), we would expect this to be achieved if there is a large consensus across interests and shared identities of states. At the same time, we may actually see evidence that states contradict the overarching policy objectives and strategies agreed upon on a macro-level of transatlantic relations.

Why Would Actors Across the Atlantic Actually Arrive at Policy Coherence?
In order for horizontal and vertical policy coherence to take shape in the context of transatlantic relations, we do not only need a willing hegemon to advertise con-gruent and coherent policies, but also a given set of mutual interests, rules, and norms amongst all transatlantic actors. This calls for a two-fold reading of transatlantic relations which allows to explain them from a rulesand norms-based approach (constructivist), on the one hand, and from an interest-based approach (realist) on the other. By simultaneously using a constructivist and realist approach we aim to explain why policy coherence in transatlantic relations is pushed or undermined for reasons of identity and/or interest of transatlantic actors (or actually not). Nonetheless, various theoretical accounts can explain why coherence/incoherence is or should be achieved-be it for reasons of the underlying actor's identity or interests, but also for reasons of institutional-administrative interests (see Marangoni & Raube, 2014) or domestic post-functionalists' constraints (see Hooghe & Marks, 2009). Yet, given the transatlantic actors' increased focus on geostrategic interests, as well as their focus on a set of common values and principles (identity), both a realist and constructivist reading of policy coherence may prove to be useful.
A first realist account may predominantly offer us to explain why policy coherence in transatlantic relations remains a "vehicle" of states' interests (Hyde-Price, 2006). In other words, coherence may not necessarily always be beneficial. Action that follows geostrategic interests of states may run contradictory to overall transatlantic coherence. Pragmatic political strategies and action remain an expression of states' interests rather than the shared identity of the pluralist security community. From a realist perspective, coherent external action in transatlantic relations can lead to an increase of external credibility, while at other times it might be more beneficial for individual states to pursue their own actions. Pragmatic choices and incoherent action are thus "natural" situations (see Marangoni & Raube, 2014;Raube & Burnay, 2018).
A second constructivist account offers us a focus on identity-related explanations of why actors would opt for policy coherence. From a constructivist perspective, horizontal and vertical policy coherence are achieved based on shared identities, values, rules, and principles across the Atlantic. Coherent action is pursued when a shared identity is a driving force of transatlantic relations, promotes Atlantic values beyond its own realm, and defends the underlying values of the West and the LIO towards other actors (see Marangoni & Raube, 2014). Overall, in Presence of inconsistency and/or absence of synergy between transatlantic organisations and member states the eyes of the constructivist theory, a pluralist security community, like the one that finds expression in transatlantic relations, will not only arrive at coherent action due to common identities, but also because it is the only way to credibly project Western norms and values externally towards other parts of the world. Especially once we zoom in on the question if actors across the Atlantic actually arrive at policy coherence in their foreign policy responses towards China, we can derive a first hypothesis from the above-mentioned theoretical accounts. Accordingly: HYP1: we expect a transatlantic actor to respond coherently to the emerging rivalry with China if its action was interest-driven and matches those of other transatlantic partners or organizations.
In other words, a match of interests across the Atlantic leads to a win-win situation in terms of overall transatlantic security. We would expect actors to activate and play towards these interests. However, equally, if coherence is not seen as beneficial, actors may opt for alternative forms of cooperation and, consequently, fail to speak a language of transatlantic cooperation (Waltz, 1993). Secondly: HYP2: we expect a transatlantic actor to respond coherently to the emerging rivalry with China if its action was identity-driven and matches those of other transatlantic partners or organizations.
In other words, in order for coherence to materialise, transatlantic identity, ideas, and values (including democracy, human rights, and the rule of law) would have to inform action, allowing research to point to leadership and action that highlight the importance of the transatlantic identity.
In order to test the two hypotheses above, we use two recent cases: the so-called concerted sanctions case in March 2021 and the so-called AUKUS case in the second half of 2021. By testing both hypotheses in both cases, we can point to different policy outcomes and, respectively, the factors that lead to (in-)coherent transatlantic responses towards China. By the same token, we may expect transatlantic coherence to be achieved if actors were to take concerted sanctions against China and, more specifically, China's human rights violations. Given the underlying transatlantic values (see NATO, 2021b), we would expect that policy coherence was reached because actors were mainly driven by subjacent common identity conceptions. In the AUKUS case, a case that is essentially about China's quest to regional hegemony in the Indo-Pacific but also about the increasingly important threat perception of China in transatlantic cooperation (NATO, 2021b), we would expect transatlantic coherence to be achieved if actors were to take coordinated defence-related action to contain China; not the least because actors were mainly driven by underlying common security and defence interests.

Methodology
Prior to the analysis, we briefly want to highlight why the concerted sanctions case and the so-called AUKUS case have been chosen. In general, both cases enable us to explain why transatlantic actors are able to respond coherently to the emerging geostrategic rivalry with China, as both cases have a direct link to the way Western actors have recently reacted to the perceived threat of China. The selection is based on the idea of choosing two very different cases in essence. On the one hand, we have a horizontal sanctions regime that includes targeted human-rights-related sanctions which, on the outset, can be perceived as being relatively non-costly (Portela, 2019). The stake for taking on such sanctions is, compared to wider country-based sanctions, perceived as low. At the same time, human-rights-related sanctions underline the importance of universal values and a rules-based international order. On the other hand, defence-related deals and cooperation, such as the AUKUS deal, can imply costly investments that serve both larger security and economic interests. The stakes are arguably high, as such deals lead to long-term strategic commitments and trust-building measures with other partners. Such defence-related matters are generally perceived to be driven by national security interests.
At the same time, the two different cases are situated in the context of the new US administration under President Biden. In other words, both cases took place during the new Biden administration, which was seen as putting an end to the ongoing transatlantic inconsistencies during the Trump administration. First of all, the selected timeframe (the early months of the new Joe Biden administration) is relevant due to the slow but sure weakening of transatlantic relations with previous US administrations and the leadership role that the US holds in the security alliance (Anderson, 2018;Riddervold & Newsome, 2021;Risse, 2016). Although the Obama period may be remembered as one of relatively harmonious transatlantic relations, it was also during his time in office that US foreign policy reorganised its priorities with the so-called "Pivot to Asia" and diverting attention and resources away from Europe (Anderson, 2018). Nonetheless, the aforementioned weakening and distrust between the transatlantic powers escalated with Trump's isolationism and unilateralism in foreign affairs (Anderson, 2018;Riddervold & Newsome, 2021). In this sense, to analyse case-studies taking place with a more pro-transatlantic and multilateralist US administration (who already re-joined the Paris Agreement and the World Health Organization) appears interesting considering Biden's outspoken intention to raise the level of ambition in US-EU relations.
Both cases are related to transatlantic relations and the geostrategic rivalry with China. First, the concerted sanctions case includes a number of different individual transatlantic actors, while the AUKUS case seems at first to be only about two individual transatlantic actors (the US and the UK). The latter case, however, is shedding light on the non-involvement of more transatlantic actors (continental Europe) that could otherwise have been involved in the making of a defence-related agreement. Indirectly, as the following analysis will show, both cases are linked to NATO as well, since NATO members have agreed to tackle the geostrategic rise of China by means of transatlantic cooperation. Second, both cases also shed light on the geostrategic rivalry of transatlantic actors with China (new contender to the US hegemony since the Russian role in world politics is declining) and their responses towards its emerging role in the international system. While the US recognises China as "the US' strategic threat of the 21 st century" (Balfour, 2021, para. 10), the EU takes a non-confrontational but cooperation-based approach towards the assertive Chinese foreign policy (European Commission, 2021). Nonetheless, the EU has also referred to China as a "systemic rival" when it comes to the promotion of "alternative models of governance" (European Commission, 2019, p. 1).
To answer the research question ("How can we explain coherent actions (or lack thereof) between actors across the Atlantic in their foreign policy towards China?") we carry out a two-fold analysis. On the one hand, we study transatlantic actors on a strategic-rhetorical level (i.e., interpreting official documents to analyse the intention of transatlantic powers to coherently cooperate or not). On the other hand, we also effectuate a more practical action-based analysis of the coherence (or lack thereof) of transatlantic actors through the material actions of the two case-studies. To this end, we use an interpretative qualitative method that focuses on a variety of documents (primary, secondary, and tertiary sources). In other words, we assess and interpret respective primary (official) sources on a strategic-rhetorical level (such as the so-called "New Transatlantic Agenda"), while we also use primary, secondary, and tertiary sources (including official documents, journal articles, newspaper articles, surveys, and reports) that allow us to assess and interpret the coordination of transatlantic relations at an action-based level. Once we have spotted the types of coherence or incoherence for the given case (horizontal and vertical), we will use the realist and constructivist lenses in order to explain the actions of transatlantic actors and to test the two elaborated hypotheses (HYP1 and HYP2).

Coherence and Incoherence in the Transatlantic Response Towards China
The following section will examine the selected two cases in light of the coherence/incoherence conceptual framework and the realist and constructivist theories.

Context
In the name of social stability, the Chinese Communist Party (CCP) has constructed a "multi-layered network of mass surveillance" in the region of Xingyang in order to standardise the behaviour of its residents (Leibold, 2020, p. 1). The CCP identifies "deviant" individuals who are subjected to transformation via re-education processes and organises their "rehabilitation" according to their "level of contamination, local practices," and willingness to change (Leibold, 2020, p. 12). Since 2017, more than one million people have been interned in these extra-judicial centers, where deteinees undergo forced indoctrination-involving "psycological and physical torture" (Leibold, 2020, p. 1). In 2020, the Australian Strategic Policy Institute counted more than 380 suspected detention facilities (Ruser, 2020).
However, multilateral transatlantic action coordinated by the US took place on March 22, 2021 to hold China accountable for its human rights violations. The US, the EU, Canada, and the UK imposed Magnitsky-style tailord sanctions on several Chinese officials, following the inspiration of the US' Global Magnitsky Human Rights Accountability Act (2016) as a transnational mechanism for human rights protection.
The EU's sanctions against China were implemented in the framework of the EU Global Human Rights Sanctions Regime, adopted in December 2020 (Council Decision of 22 March 2021Council Implementing Regulation of 22 March 2021. In retaliation, China sanctioned 10 European individuals (including members of the European Parliament and scholars) and four entities. While its intention may have been to initiate its reprisal by the weakest, it backfired, as it caused the EU-China Comprehensive Investment Agreement (CAI) to be suspended in May 2021, and the EU and the US to get closer (Kleinfeld & Feldstein, 2021).

A Case of Coherence?
First of all, the concerted sanctions case shows vertical coherence at a strategic-rhetorical level. Already in 2016, during the Warsaw meeting, NATO heads of state stressed the importance of the shared underlying values driving the sanctions against China: "NATO is an alliance of values, including individual liberty, human rights, democracy, and the rule of law. These shared values are essential to what NATO is and what it does" (NATO, 2016, para. 129). This commitment has been consistently upheld by the organisation. More recently, in June 2021, at the Brussels meeting of the North Atlantic Council, NATO heads of state reaffirmed the commitment of the organisation towards "the values we share, including individual liberty, human rights, democracy, and the rule of law. We are bound together by our common values…the bedrock of our unity, solidarity, and cohesion" (NATO, 2021b, para. 2). Moreover, in the NATO 2030 Agenda factsheet (also released in June), proposal number 5 calls to "uphold the Rules-Based International Order" because it is "under pressure from authoritarian countries, like Russia and China, that do not share our values. This has implications for our security, values, and democratic way of life" (NATO, 2021a, p. 3). Overall, we find vertical coherence in the absence of inconsistencies between NATO and its member states' strategy and actions, arriving at no contradictions-both before and after the case itself took place.
Secondly, we find horizontal coherence on the actionbased level: Not only do EU and the US not contradict each other's policies, but generate synergetic policy-making (concerted sanctions) and added value, pulling their forces towards a specific goal (to hold China accountable for its human rights violations) without inconsistencies. Although the sanctions are largely emblematic, they are a potent symbol for several reasons. We are witnessing a convergence of approaches against China's repression: While the US would have been expected to take a more confrontational approach, Europeans may have rather opted for more conciliatory positions (Kleinfeld & Feldstein, 2021). In this vein, we find internal coherence and consensus within the EU. This was the second time since 1989 (when an arms embargo was implemented following the Tiananmen Square crackdown) that the EU imposed sanctions on China. This means that commercial ties with China, the suspension of the CAI agreement, and the diverging interests among EU member states did not obstruct the path to transatlantic cooperation in the area. It is also relevant considering that restrictive measures in EU law require a unanimous Common Foreign and Security Policy (CFSP) decision. At the same time, transatlantic synergetic policy-making has also provided added-value and inspired other countries to also protect the LIO values and condemn Chinese crimes. Three days after the sanctions were announced, lawmakers in Tokyo formed a "cross-party" alliance to create Magnitsky-style legislation while the Japanese ruling party investigates the abuses towards the Uighurs (Kleinfeld & Feldstein, 2021). New Zealand and Australia have also publicly welcomed the sanctions, which is a big step taking into account these countries' commercial ties with China (one-third of Australia's exports are directed to China and it would not be the first time that a trade embargo is imposed against Australian criticism).
Overall, our analysis points to a convergence on both strategic-rhetorical and action-based levels of transatlantic relations. But how can we explain coherence as an outcome in the concerted sanctions case? First, when applying realist lenses, one finds the concerted action to also be coherent because it was on both transatlantic actors' interest to sanction China, while exerting international pressure on one of its defining characteristics: its authoritarian model and its abuses. On the one hand, it is beneficial to the US because it allows for using human rights accusations as a tool to keep China "in check" and on notice. On the other hand, the EU joins in because sanctions are the only tool in its arsenal, and it is on a topic where member states can-in relative termsarrive more easily at consensus. Second, in constructivist terms, the coordinated response to Chinese authoritarianism is coherent because it is informed and driven by shared identities, rules, and principles across the Atlantic which credibly punish Chinese violations of human rights and protect the LIO values. In fact, the collective transatlantic identity may have been a greater driving force than the factors arising from a purely interest-based approach. While one may argue that the sanctions came at a "low cost" for the transatlantic powers, Chinese retaliation brought back more sanctions and caused the CAI agreement to be suspended after seven years of negotiation between the EU and China.
To conclude, transatlantic actors have found an overall coherent answer to China's repression and violations of human rights (which project an alternative authoritarian model to the LIO) because common identities and, to a lesser extent, interests have matched amongst transatlantic actors. In other words, both hypotheses were confirmed. As such, we can substantiate that the concerted sanctions case shows not only considerable horizontal and vertical coherence, but also that both theories help us to explain the reasons why actors embedded in transatlantic relations were able to produce coherent action. Not only did actors commit to horizontal and vertical coherence rhetorically in their strategic thinking about how to address their rivalry with China, but they were also committed to set words in action and launch the sanctions-even at a higher price than expected (see the case of the EU and the suspension of the CAI agreement).

Context
On September 15, 2021, the US, the UK, and Australia announced a security pact (the AUKUS deal) that signals an Asia-Pacific power shift (The White House, 2021). The overarching idea is to create a security deterrence to China: one designed to undermine China's quest to regional hegemony in the Indo-Pacific. The agreement encompasses the exchange of information and technology in a variety of fields. However, a key component is the nuclear-powered submarines, which will make it harder for China to "project power at sea and control critical lines of communication" with nearby countries (Walt, 2021, para. 5). This component also infuriated France. Australia cancelled a €50 billion agreement signed in 2016 with the French company DCNS (known as Naval Group) whereby Australia's Navy would acquire 12 Barracuda diesel-powered submarines. Instead, under the tripartite agreement, the US and the UK would provide Australia with consultation on technology to produce nuclear-powered submarines in Australia. The main difference between the two types of submarines is their propulsion technology (Pfeifer et al., 2021). French officials argue to have offered in June 2021 the possibility to convert the submarines into nuclear-powered ones (Pfeifer et al., 2021).
Although the ambassador of France to the US was sent back on September 22, it was the first time in the 243 year-long alliance between the nations that a top diplomat had been withdrawn. France´s Foreign Affairs Minister referred to the deal as a "stab in the back" (Darmanin & Sheftalovich, 2021, para. 2). He also stated that the AUKUS deal "constitutes unacceptable behaviour between allies and partners, whose consequences touch the very foundation of what we do with our alliances and our partnerships and on the importance of the Indo-Pacific for Europe" (Mallet, 2021, para. 3).
On the very next day after the AUKUS deal was made public, Josep Borrell announced the European strategy for the Indo-Pacific, which was overshadowed by the deal. Borrell expressed the following during the press conference regarding the AUKUS pact: "We were not informed, we were not aware…we were not even consulted. I, as [the EU's] High Representative, was not aware of it, and I assume an agreement of such nature wasn't brought together overnight." (Liboreiro, 2021, para. 8).

A Case of Incoherence?
In comparison with the concerted sanctions case, the AUKUS case shows lack of policy coherence and consistency. At a strategic-rhetorical level, research findings point at both horizontal and vertical incoherence. The horizontal incoherence of transatlantic actors becomes evident when we look at the "New Transatlantic Agenda" (June, 2021) by the US and the EU: We intend to continue coordinating on our shared concerns, including…regional security issues. We remain seriously concerned about the situation in the East and South China Seas and strongly oppose any unilateral attempts to change the status quo and increase tensions. (European Council, 2021, p. 5) The intentions specified by the agenda were not met by US actions. Moreover, it was now the US, the UK, and Australia that were criticized for a deal which according to the spokesman of the Chinese Foreign Ministry, Zhao Lijian, "seriously undermined regional peace and stability, aggravated the arms race and hurt international nonproliferation efforts" (Kuo, 2021, paras. 2-3). Moreover, the AUKUS case also reveals vertical incoherence between NATO and its members. This shows when analysing the June NATO Brussels Summit from 2021: NATO's fundamental and enduring purpose is to safeguard the freedom and security of all its members by political and military means. The evolving security environment increasingly requires us to address threats and challenges through the use of military and non-military tools in a deliberate, coherent, and sustained manner. (NATO, 2021b, para. 8; italics by the authors) Again, the AUKUS case and US actions show a mismatch between NATO's ambitions and the actions taken by its members. Following the Brussels summit, the US could have counted on the EU in its foreign policy towards the Indo-Pacific and against China through the use of a mixture of defence-related and political means. Instead, the US preferred to involve partners that rather opted for launching a military agreement.
At an action-based level, the AUKUS case shows that isolating France (the one EU member state that has been pushing for a European strategy for the Indo-Pacific since 2018) and, most importantly, not to warn EU member states about the AUKUS announcement (weeks after the US' unilateral withdrawal from Afghanistan), weakened transatlantic relations. Hence, at an action-based level, we find horizontal incoherence as the US did not count on the EU in order to avoid inconsistencies in their foreign policy against China, let alone to create synergetic policy-making. The evolving AUKUS case undermined the trust in the already fragile security alliance in general, and among NATO members more specifically (Balfour, 2021;Manson, 2021). Contrary to this case, in other instances, the EU and the US have cooperated using, for example, "good cop, bad cop" tactics that proved successful in deescalating geopolitical tensions, such as the EU talks with Iran that eventually led to the non-proliferation negotiations and the Joint Comprehensive Plan of Action (JCPOA) (Balfour, 2021, para. 11). Instead, the diminished trust after the AUKUS case undermines the possibility of the US and the EU to work together in other policy areas such as climate change or trade in the Indo-Pacific region. For example, in the latter field, China has taken the initiative and applied to join the Progressive Agreement for Trans-Pacific Partnership (CPTPP), a free trade agreement signed under the Obama administration in 2016 but abandoned by Trump.
Overall, from the findings of the AUKUS case, we see that the two levels of analysis do not converge for this case-study, as there is a contradiction between words and actions (i.e., inconsistencies stemming from incoherent policy-making).
Both realism and constructivism help to explain this case "in tandem." From a realist read, coherence shall not always be pursued if it is not beneficial and consistent with the nation's interest. The AUKUS deal is necessary for the US to contain China. Given the non-confrontational stance of the EU towards China in its Indo-Pacific strategy (European Commission, 2021), its lack of military capabilities, and the fact that EU increasingly recognises climate change and the protection of biodiversity as the "greatest threat of the 21 st century" (Balfour, 2021, para. 13), the US may not conceive Europe as a credible or trustworthy security ally. It then appears coherent, from a US-American perspective, to exclude the European allies and create an alternative partnership with the UK and Australia. Nonetheless, also from a realist read, a hegemon needs to secure its allies in order to appear credible and maintain its role; a bare minimum would have been to inform the EU about a security pact "in the making" or, at a maximum, to include it through the use of non-military means as part of its foreign policy towards China. From a constructivist angle, the AUKUS deal signals a geopolitical and geostrategic struggle against China, because even though relevant Western actors (including the UK and Australia) "stroke back" to contain China's quest to regional hegemony in the Indo-Pacific, overall transatlantic identity, including continental Europe, fell short of creating momentum. On a positive note, constructivism, however, can explain the Europeans' reaction to the AUKUS deal as a plea for taking decisions based on a collective transatlantic identity where all parties are informed about key geostrategic actions that affect relevant international affairs.
All in all, for the present case, transatlantic actors did not find a coherent answer to China's rivalry because the US played towards its own geostrategic interests solely and prioritised alternative cooperation with the UK and Australia excluding a common identity-based transatlantic approach (mismatch). Neither HYP1 nor HYP2 were confirmed. Rather, the analysis showcases significant horizontal and vertical incoherence and severe divergence between both levels of analysis-as actors were not able to set words in action.

Conclusion
The election of Joe Biden as US President was celebrated across Europe as an opportunity to revive transatlantic relations; a fresh start after the four years of incertitude, weakening, and instability under the administration of Trump. Using the early Biden presidency as a timeframe and the key rise of China as a rival and contender (subject-matter of much of transatlantic powers' policymaking), the article departed from the research question "how can we explain coherent actions (or lack thereof) between actors across the Atlantic in their foreign policy towards China?" By applying realist and constructivist theoretical accounts to a coherence framework of transatlantic relations in two different cases, the concerted sanctions case and the AUKUS case, we were able to point at coherent and incoherent policy outcomes. In the case of concerted sanctions against China, the article showed that transatlantic actors have found an overall coherent answer to China's repression and violations of human rights because common identities and interests matched amongst transatlantic actors. Both constructivist and, to a lesser extent, realist accounts helped us to explain the coherent outcome. In the AUKUS case, however, transatlantic actors did not find a coherent answer to China's rivalry, not the least because the US focused on its own geostrategic interests and prioritised alternative cooperation with the UK and Australia, ruling out a wider transatlantic approach. Especially realist theoretical accounts helped us to show the incoherent outcome, while constructivist accounts remained an asset to explain why transatlantic identity fell short of creating momentum. The differences between the two cases furthermore became evident when we looked at the different dimensions and levels of coherence. In the concerted actions case, actors committed to horizontal and vertical coherence strategically and they were also committed to set strategy in action and actually launch the sanctions. The AUKUS case however showed significant horizontal and vertical incoherence and that transatlantic actors were not able to set strategy in action.
The findings of the article point to several theoretical and empirical implications. On the one hand, both realist and constructivist accounts proved useful to explain the outcomes of the two cases. In other words, while coherence remains a valid conceptual tool to explore consistency and synergy across and amongst transatlantic actors and organizations, it is thanks to the theoretical capacity of realist and constructivist accounts that we can explain why transatlantic relations are coherent/incoherent. As such, the article confirms that a theoretically-infused coherence framework is not only useful to explain the coherence/incoherence of a polity, such as the EU, but also a "lighter" governance arrangement, such as the one of the transatlantic security community. Empirically, the article furthermore confirms that transatlantic relations may not necessarily strengthen, neither weaken, due to a change of US administration. The findings rather point to a continuation of a mix of cooperation and non-cooperation, as we have known it from previous administrations before Trump. The difficulty to arrive at a coherent response towards China underlines this mix in the first year of the Biden administration. While the AUKUS case may potentially even weaken transatlantic relations and undermine trust amongst partners, the concerted sanctions case shows that transatlantic relations can also witness coherence and strength, if actors can agree on matching action. While one can see greater coherence regarding the defence of the LIO values when compared to the previous US administration, the security realm may continue to be a source of incoherence in how transatlantic powers approach China.
TRANSAT project, financed by the Research Council of Norway, project number 288752.