A sigh of relief swept across Europe when it became clear that Joe Biden would replace Donald Trump in the White House. New leadership in the United States would mean that after four years of disruption to the transatlantic relationship, an era of constructive cooperation on bilateral and global issues was at hand.

But in recent weeks, that previous sense of relief has given way to nervousness as the US political scene has plumbed new depths of dysfunction. America’s democratic institutions have withstood assaults unlike anything seen since the Civil War. The ransacking of the US Capitol on 6 January—broadcast live to a stunned world—will not soon be forgotten.

The hatred and disdain for democracy exhibited by the insurrectionists will not disappear with Trump’s departure. Millions of Trump supporters around the country will maintain the false belief that the election was stolen. Trump has left American society deeply wounded and Europe with an abiding sense of nervousness and concern for its longtime ally’s future.

Much has changed since early December, when the European Commission released a document outlining its vision for renewed EU–US cooperation. ‘With a change of administration in the US, a more assertive Europe and the need to design a post-corona world’, EU leaders saw a ‘once-in-a-generation opportunity to design a new transatlantic agenda for global cooperation’. Hopes were high. Biden and his impressive team of advisors have made clear that they will reach out to friends and allies to address pressing global challenges such as climate change, threats to public health and the rise of China.

But while European institutions and governments will remain ready to answer America’s call, they should not assume smooth sailing. The winds have changed. A poll of 11 EU member states commissioned by the European Council on Foreign Relations (ECFR) shows that European attitudes towards the US have shifted substantially during the Trump era. A majority of respondents in EU member states believe that the US political system is broken, that Europe can’t rely on the US for its defence, that China will be more powerful than the US within a decade and that Europe should not take sides in a conflict between the two.

Across the countries polled, 51% of people do not think that the US can overcome its internal divisions and invest in addressing key global issues that concern the future of Europe. Though there are of course differences between countries, they are small. Even in the United Kingdom, with its ‘special relationship’ with America, 81% of respondents believe that the US political system is completely or somewhat broken. Only in Hungary and Poland do a majority believe otherwise.

And while other polls show that attitudes towards China have hardened across Europe, 60% of Europeans would prefer that the European Union stay out of the Sino-American rivalry. Only 22% of respondents in the ECFR poll think that Europe should back the US, while 6% think it should side with China. Attitudes about the US are far more reserved than in the past, and confidence in Europe’s ability to shape its own future has grown (whether that outlook reflects reality is another matter).

This clear shift in European attitudes could not come at a worse time. In a world of changing power relationships, US–EU cooperation is urgently needed. There is no way for either side to prevail against global challenges by going it alone. The transatlantic link is the foundation on which wider global cooperative networks must rest.

But Europeans’ nervousness following the recent events in the US cannot simply be willed away. It will linger, implying at least some impact on diplomacy and policymaking. The immediate risk is that America’s political turmoil will bolster those who are already calling for Europe to blaze its own trail, build new barriers or retreat from the world. If Europe’s traditional and natural ally is no longer reliable, what other choice is there? That’s the question now hanging over European policy and strategy debates.

Biden, of course, will be welcomed with near-universal jubilation across most of Europe. But it will take much longer to settle the question of whether Trump was an historical aberration or a harbinger of what is yet to come.

As such, the shift in European public opinion will pose an ongoing challenge for US and European leaders alike. The Biden administration must do whatever it can to restore trust in US society and policymaking, and European leaders must convince a sceptical domestic audience that it should support measures to restore transatlantic ties. The ECFR poll suggests that European leaders have their work cut out for them. But failure is not an option. With new leadership in Washington DC, now is the time to ensure that the nightmare of the past four years is never repeated.