Donald Trump or Kamala Harris? In Brussels, both the EU and NATO are anxiously and somewhat nervously awaiting the outcome of the US presidential election.

The unpredictable Republican candidate has already cracked down on defaulters in NATO, criticized the sums released by Washington for Kiev and mentioned the possibility of imposing new tariffs on goods imported from Europe.

The November 5 victory of his Democratic opponent will no doubt be greeted with relief by Brussels, but Europeans insist there is a need – regardless of the outcome of the presidential election – to prepare for deep and lasting changes in their relations with the US.

In the event of a Kamala Harris victory, the EU countries feel that they will be in familiar territory, although “we don’t know much about her plans for foreign policy”, pointed out a diplomat at NATO.

But Trump’s possible return to the White House is cause for concern. “There is a kind of paralysis on the European side in the face of the scale of the challenge,” said Martin Quenseth, a defense expert at the Paris-based German Marshall Fund.

All European leaders remember the threats that the billionaire made again in February: if you don’t pay more for defense, you will have to fend for yourself against the Russian threat.

Already many countries of the Alliance have increased their defense spending to 2% of their GDP. Now 23 of NATO’s 32 members have met this goal, up from just three a decade ago.

But they know they will need to do more, regardless of who wins the US election. The Republican candidate is not the only American president who has asked Europe to take a bigger share in the defense sector.

“He has a ‘Trump’ way of saying things, he communicates like that a lot, but the message that Europe needs to do more is completely legitimate,” commented one diplomat.

Although many Alliance officials hope to avoid a clash with Trump over NATO, Europeans are even more concerned about the future of Western support for Ukraine.

“Europe may find itself supporting the Ukrainian resistance alone,” warned French MEP Raphael Glicksman.

The former US president, who dreams of making a spectacular return to Washington, has repeatedly threatened to end US aid to Kiev and has said he will end the war within 24 hours, without explaining how .

Europe may have no choice but to continue supporting Ukraine alone. However, the European front is also in danger of disintegrating rapidly.

“European capitals risk being forced to increase pressure on Kiev to start negotiations with Moscow, against the will of the Ukrainians themselves,” Gliksman warned.

Until the announcement of the results of the American elections, Europe is in a state of waiting. “We’re trying to continue to do on our side what we’ve always done, that’s the feeling in NATO,” explained one diplomat.

On trade, the EU believes this time it will be better equipped for a conflict should Trump return to the presidency.

“The EU is better prepared for a new Trump administration”, assured a diplomat from Brussels.

Already on the table of EU officials is a list of US products that may face tariffs in response to US tariffs on European goods. However, diplomats and EU officials insist that this measure will be a last resort. “Nobody in Brussels is looking for escalation,” one of them said.

The first test will be in March, when the EU’s exemption from US-imposed tariffs on steel imports expires.

Trump in 2018 imposed tariffs on steel and aluminum imported into the US from several countries, including those from the EU. Joe Biden kept the tariffs in place but exempted the EU from the measure for a transition period that ends in March.

Europeans worry the Republican will impose even higher tariffs. If Harris wins, they don’t expect the Democrats to be particularly generous on the issue, but at least they expect “good faith” negotiations, according to a diplomat.

With Harris in the presidency, “there will be a willingness to continue to look for areas of cooperation, to try to avoid useless conflicts”, estimated Greta Pais, a former adviser at the office of the US Trade Representative.