By Alastair Macdonald and Gabriela Baczynska
BRUSSELS (Reuters) - For Europe, already reeling from Britain's decision to leave its 28-member club, Donald Trump's election introduces a host of new uncertainties it is ill-equipped to tackle.
Preoccupied by a growing anti-establishment mood across the continent, the European Union's leaders gave little thought to the idea a man dubbed "the pioneer of a new authoritarian and chauvinist international movement" by Germany's deputy chancellor could take power in the United States.
The day before, one of the EU's leaders had confided a contingency plan of "crossing ourselves and praying". The day after, as they pledged to work with Trump, a senior EU diplomat summed up their dilemma.
"Since we have refused to really think through this scenario, we have a list of questions that need to be answered, but almost everything is a big unknown," the envoy told Reuters.
For some, Europe must now step up and take more responsibility, both for its own security and the wider world, if the entrepreneur makes good on campaign talk of limiting U.S. defense commitments and other engagements abroad.
Trade relations, climate change, Russia and tackling Islamic State are all areas where Europe may have to forge its own path if a Trump-led Washington pulls back from the global stage.
"This is another wake-up call," said Manfred Weber, a German ally of Chancellor Angela Merkel who leads conservatives in the European Parliament. "It is now up to Europe. We must be more self-confident and assume more responsibility.
"We do not know what to expect from the USA."
Belgian Foreign Minister Didier Reynders told Reuters a Trump White House "may help some people in Europe understand that we need to reinforce defense cooperation among Europeans".
But EU leaders know that euroskeptic radicals, inspired by Trump and Britain's vote to leave the bloc in June, could exploit any attempt to tighten cooperation to condemn them to the same ignominious electoral fate as Hillary Clinton.
East Europeans fret President Vladimir Putin may use Trump's vow to improve ties with sanctions-hit Moscow to extend Russian influence, as in Ukraine. The Norwegian head of NATO felt obliged to spell out that Trump could not renege on security guarantees.
"PUTTING ON A BRAVE FACE"
"Europe cannot blink after Brexit, after the election of Donald Trump," French Foreign Minister Jean-Marc Ayrault said of the political earthquake in Washington, which, 27 years to the day since the fall of the Berlin Wall, continues to provide the lion's share of military muscle to defending the continent.
"Europe must stand together more, be more active and go more on the offensive," Ayrault said. "Even just to protect itself."
Privately, senior officials question its ability to do that.
"Europe will need to do more to take care of its own - but are we capable?" a senior European diplomat asked. The EU has been riven with tensions over economic policy, the Syrian refugee crisis and Britain's exit, and remains very divided.
Another senior EU diplomat told Reuters: "This changes the business model of the EU. But we have no idea how."
He dismissed suggestions a U.S. withdrawal from some engagements could offer benefits by obliging Europeans to invest more in their cooperation and spend more on their own defense: "That's not a silver lining. That's putting on a brave face."
EU foreign ministers called a special meeting over dinner on Sunday to discuss what Trump's America will mean for Europe.
Giles Merritt of pro-EU Brussels think-tank Friends of Europe said leaders had no time to lose to "head off trouble" and could revive their own Union by helping defend global stability. They "must ... fashion a common European response ... before President Trump sets foot in the Oval Office", he said.
CHANGE THE WHOLE SYSTEM?
It was a result few in Europe had wanted, barring Hungary's authoritarian prime minister Viktor Orban. European leaders -- and Obama Administration envoys -- were reduced to highlighting the lowest common denominators of shared history and ideals in giving assurances of continued cooperation.
After a U.S. campaign marked by accusations of racism and sexism, Merkel, preparing for her own election battle next year, said she would work with Trump on the basis of shared values that included "respecting ... people's dignity regardless of their origin, the color of their skin, religion (or) gender".
Donald Tusk, the former Polish premier who chairs EU summits, responded to what he called "new challenges" and "uncertainty over the future of our Transatlantic relations" by stressing centuries of blood ties across the ocean.
French President Francois Hollande stressed a need for even stronger Transatlantic cooperation to tackle climate change, Islamist security threats and the global economy.
Washington's ambassador to NATO could offer no detail on the incoming administration's policy but reassured European peers in Brussels that NATO had always been a "bipartisan venture".
Anthony Gardner, outgoing President Barack Obama's envoy to the EU, said change was possible in areas including sanctions on Russia, support for Ukraine, nuclear proliferation, trade, NATO and the Middle East, but added: "Let's wait to see who appoints as his key advisers."
He did not see Washington abandoning a key partner for the past 50 years, but his reassurance did not quell a sense of near panic among some senior officials in Brussels.
One said grimly: "This is bad. Brexit was a stupid and damaging mistake but the people running it are not complete lunatics. Now we have a populist in power who can change the whole system as we know it."
(Editing by Philippa Fletcher)