With the war in Ukraine soon to enter its third year, Trump sparked outrage among Western partners on Sunday after suggesting the United States might not protect NATO allies who are not spending enough on defence from a potential Russian invasion.

Warsaw, Paris and Berlin see EU unity on defence and a ramping up of the 27-member states' support for Ukraine as crucial at a time when the U.S. backing of Kyiv is wavering amid political infighting in Washington.

"Europe has to get its act together ... this is a matter of answering a question about what will happen if Trump wins. We don't have time, we must have bigger defence industry capacity," said a Polish government source.

The source added that Europe urgently needed joint production of ammunition and that Poland was no longer blocking "strategic autonomy" - making Europe less dependent on others.

The shift has been noticed elsewhere in Europe.

"Now for the first time a Polish government is saying that strengthening the European Security Defence Capabilities area is not a contradiction to a strong NATO," said Dietmar Nietan, a German official in charge of cooperation with Poland.

Relations between Poland and Germany were strained by eight years of nationalist rule in Warsaw. The campaign for October's Polish election saw the Law and Justice (PiS) party, in power from 2015 to 2023, cast Berlin as villain on everything from migration to energy.

However, analysts say the return of former European Council President Tusk to prime minister makes it easier to reinvigorate the "Weimar Triangle" platform of political cooperation between Germany, France and Poland created in 1991.

EASTERN EUROPEAN CONCERNS

A second Polish government source said the format gave Warsaw a way to present concerns of eastern EU members. "We talk to our neighbours first, we understand their concerns and then we are able to formulate these concerns on behalf of the region to our German and French colleagues," the source said.

Alongside Tusk's talks with French President Emmanuel Macron and German Chancellor Olaf Scholz, foreign ministers will meet in Paris on Monday.

A French diplomatic source said that injecting new energy into the European project was necessary in an important electoral year for Europe and the United States.

The French source said talks would focus on issues from combating Russian disinformation and helping Ukraine to strengthening the European defence industry.

"These three countries can create a ripple effect on the rest of the EU if they agree on the key issues," the diplomat said.

One delicate subject is the question of German reparations for Poland's World War Two losses.

PiS demanded 6.2 trillion zlotys ($1.55 trillion) in reparations but was rebuffed by Berlin. The new Polish administration has taken a different approach, with Foreign Minister Radoslaw Sikorski saying Germany should think in a "creative" way about the issue.

"The only possible way to resolve the reparations issue is to turn it into a discussion about security and defence," said Piotr Buras, a senior policy fellow at the European Council on Foreign Relations think tank.

"German defence investments, including in boosting Poland's security, would be a forward-looking answer."

($1 = 4.0093 zlotys)

(Reporting by Marek Strzelecki and Alan Charlish in Warsaw, Sarah Marsh in Berlin, John Irish in Paris; Editing by Andrew Cawthorne and Alex Richardson)

By Alan Charlish