– America's traditional allies are on the lookout for new friends.

They have heard the mantra "America First" from the new president, divining a Trump Doctrine: Global cooperation last.

Europeans have taken note of President Donald Trump's denigration of the European Union and his apparent esteem for Russian President Vladimir Putin.

In Asia and Latin America, leaders have absorbed the deepening possibility that Trump will deliver on threats to impose punitive tariffs on Mexican and Chinese imports, provoking a trade war that will damage economic growth and eliminate jobs around the world.

Some allies are shifting focus to other potential partners for new sources of trade and investment, relationships that could influence political, diplomatic and military ties. Many are looking to China, which has adroitly capitalized on a leadership vacuum in world affairs by offering itself — ironies notwithstanding — as a champion for global engagement.

"We've always said that America is our best friend," Jeroen Dijsselbloem, president of the Eurogroup — comprising finance ministers from countries sharing the euro currency — said at the World Economic Forum in Davos, Switzerland, this month. "If that's no longer the case, if that's what we need to understand from Donald Trump, then of course Europe will look for new friends."

"China is a very strong candidate for that," he added. "The Chinese involvement in Europe in terms of investment is already very high and expanding. If you push away your friends, you mustn't be surprised if the friends start looking for new friends."

On Wednesday, Chancellor Angela Merkel of Germany spoke with Premier Li Keqiang of China. "The two spoke in favor of free trade and a stable world trade order," a German government spokesman said.

The swift reassessment of trade relations — a realm in which Trump is directly threatening the order that has prevailed since the end of World War II — only amplifies the potential for a shake-up of the geopolitical framework.

Trump has criticized NATO as obsolete while demanding that member states pay more, calling into question the alliance that has maintained security across much of Europe for more than six decades. He has provoked fears of a clash with China beyond issues of commerce by taking a congratulatory call from the president of Taiwan, the self-governing island that Beijing claims as part of its territory. In shutting U.S. borders to people from predominantly Muslim countries, Trump risks inflaming tensions with Middle Eastern nations while widening a void with democratic allies over basic values.

Through the fractious campaign, weary sophisticates dismissed the extreme talk from the Trump camp as political bluster. Even if he won, he would never follow through on his threats, particularly in trade where his business sensibilities would prevail.

But that conventional wisdom looks to be crumbling. First, Trump delivered on a promise to withdraw from the Trans-Pacific Partnership, a trade agreement forged by the Obama administration.

Then, on Thursday, his administration appeared to embrace a Republican proposal to impose a 20 percent tax on all imported goods while asserting the proceeds would pay for a wall along the Mexican border. Word of the tax emerged as President Enrique Peña Nieto of Mexico canceled a visit to Washington to protest the promised wall — resonating as the potential first salvo in a trade war.

"I'm incredibly concerned that the Trump people mean what they say," said Chad P. Bown of the Peterson Institute for International Economics. "One would hope that they are using this as a negotiating tactic. But even if you are, that's an extraordinarily dangerous game to play."

Most experts have assumed the responsibilities of governance would temper Trump's trade posture. Given that nearly one-third of all U.S. trade is conducted with China and Mexico, a rupture risks severe economic damage. "The idea of trade wars these days, what politicians have in mind is really a 19th-century or early 20th-century conception of trade," said Gianmarco I.P. Ottaviano, a trade economist at the London School of Economics. "You don't even know who you're going to hurt with these kind of things. You're probably going to destroy American jobs in the end."

With the U.S. and Britain pursuing nationalist aspirations and multilateral institutions seemingly endangered, the world suddenly seems short of responsible supervision. China is working to assume the mantle. President Xi Jinping of China last week used an address in Davos to submit his nation's bid as a reliable champion of expanded trade.

China does not have free elections. China jails labor organizers, while lavishing credit on state-owned enterprises. All of this makes Xi an ironic choice as an icon for free trade. Yet Xi's speech was so successful that it won the embrace of business people and world leaders alike.

At a lunch in Davos two days after Xi's address, a Berlin-based private equity fund manager, André Loesekrug-Pietri, stood in a dining room full of more than 100 people and predicted the dawning of a new era.

"We heard a Chinese president becoming the leader of the free world," he said.