Since Donald Trump took control of the White House this year, European leaders have been grappling with how they can handle the iceier relations between the U.S. and Europe.

In a Washington Post article published on Sunday, Camille Grand said that the Europeans had a “serious problem” with their readiness. They are working to solve it, but this takes time. If Trump says, “I am going to withdraw U.S. soldiers from Germany due to the trade deficit,” that is much harder to handle than saying we will do it within X years.

As European leaders become more concerned about security in Europe in Trump’s second term, the Washington Post reports that many leaders fear that Trump is far too friendly towards Moscow. They also expect that he will withdraw the roughly 20,000 U.S. soldiers that were sent to the continent after the full-scale Russian invasion of Ukraine.

A NATO diplomat said that he would not be shocked if, at some stage, [those soldiers] return to their base in America. He noted that the troops had been sent to Europe during a time of emergency, and their departure “would be a return to the normalcy.”

According to the Center for Strategic and International Studies, the number of U.S. soldiers in Europe fluctuates between 75,000 and 105,000. The higher number is due to the increase in troops ordered by Biden.

But Trump’s administration has assured that no plans are imminent for an extensive reduction in forces on the continent.

Recent events have heightened those fears, such as Vice-President JD Vance’s comments at a Munich security conference where the American leader criticised European leaders for allegedly straying from values like freedom of expression and Trump’s growing rift with Ukrainian president Volodymyr Zelenskyy.

The American Presidents of both Parties have warned European Leaders of this potential move of troops from Europe for over a decade. As the U.S. tries to concentrate more efforts on the rising threat from China in the Indo-Pacific region, Europe is left with a larger share of its security.

The U.S. military footprint in Europe has already fallen dramatically since the end of the Cold War, according to CSIS data. CSIS’s data show that the U.S. military presence in Europe has declined dramatically since the Cold War ended. In the 1950s and 60s, when hostilities were at their height between the U.S.A. and the Soviet Union, nearly 500,000 U.S. troops were deployed on the continent. At the beginning of 1990 and the end of the Cold War, there were approximately 350,000 U.S. soldiers in Europe. This number dropped to over 100,000 by the turn of the century.

The European Union leaders are now concerned that despite the warnings they have received, the timetable for removing troops from Europe could be accelerated under Trump. This would leave security gaps in European countries, which the EU is not yet capable of filling.

Nigel Gould Davies, former British diplomat at the International Institute for Strategic Studies and Senior Fellow, said to the Washington Post: “I worry about the level of confidence that Europe can have, considering President Trump’s volatile nature.”