2| M AZARR & F IOTT The United States and the demands of European commitments US views on European security today reflect an unusual and possibly unstable tension: a strong element of largely traditional ideas about the importance of Europe and the essential role of US leadership, alongside a brewing disaffection with US global commitments and a seemingly unending frustration with burden sharing issues. It is not clear where this more dubious viewpoint is headed, or how extreme it will become. O ne American president has already expressed a desire to withdraw the United States from NATO, and since then the broader substructure of American politics has become even more disrupted. Less radical versions of this contrarian view reflect a waning of classic US opposition to a stronger European security role and more urgent demands for burden sharing. One thing seems certain – post-Ukraine, the US stance toward Europe is in more flux than at any time since 1945. Th is can be seen regarding two key issues, those being the relative emphasis on Europe as opposed to Asia and the US position on the EU’s new Strategic Compass. Defining success in the‘pivot’ The war in Ukraine has called into question the most significant over-arching recent judgement in US national security str ategy: the choice to‘pivot to Asia’, to identify China clearly‘as our most consequential strategic competitor and the pacing challenge for the Department’. Some believe that this focus is now threatened by the renewed commitment to Europe, Russia and NATO 1 . Part of the problem in making this assessment, however, is that it was never clear how to judge the success of the pivot to Asia. The idea emerged in 2011, in a speech by President Barack Obama which promised that the United States was‘all in’ on its commitment to Asia-Pacific security and an accompanying essay by then-Secretary of State Hillary Clinton. Neither of these statements suggested that the United States would abandon or even downplay other commitments in favour of Asia. T he renewed focus on Asia was not so much an effort to abandon Europe as a balancing exercise but rather recognising the relative underinvestment in the region in areas such as economic aid and security cooperation. Nor is there any clear threshold for measuring the sufficiency of the pivot. Advocates of a stronger regional military posture demand more US capabilities in the region, but it is not clear 1 Elbridge Colby, the hawkish penholder behind the Trump Administration’s 2018 National Defense Strategy, has also been issuing the most urgent warnings that a US recommitment to Ukraine will undermine the pivot to Asia, and US capabilities to deter and defeat potential Chinese aggression. He has made this argument primarily on Twitter. See for example https://twitter.com/elbridgecolby/status/1524030030430588930 .