New York. Donald Trump ran on a return to his "America First” foreign policy platform. The US, he said, could no longer afford to be the world's policeman. On his watch, he pledged, there would be no new wars.

But since winning a second term, the president-elect has been embracing a new imperialist agenda, threatening to seize the Panama Canal and Greenland — perhaps by military force — and saying he will use economic coercion to pressure Canada to become the nation's 51st state.

“Canada and the United States, that would really be something. You get rid of that artificially drawn line, and you take a look at what that looks like and it would also be much better for national security,” Trump said of the world's longest international border and the US's second-largest trade partner.

Such talk of undermining sovereign borders and using military force against allies and fellow NATO members — even if said lightly — marks a stunning departure from decades-old norms about territorial integrity. And it is rhetoric that analysts say could embolden America's enemies by suggesting the US is now OK with countries using force to redraw borders at a time when Russia is pressing forward with its invasion of Ukraine and China is threatening Taiwan, which it claims as its own territory.

“If I'm Vladimir Putin or Xi Jinping, this is music to my ears," said John Bolton, Trump's former national security adviser-turned-critic, who also served as ambassador to the United Nations.

Trump's language, reflecting a 19th-century world view that defined European colonial powers, comes as international allies were already grappling with the implications of his return to the world stage.

Gerald Butts, outgoing Canadian Prime Minister Justin Trudeau’s former top adviser and a longtime close friend, said Trump seems more emboldened than when he first took office in 2017.

“I think he’s feeling a lot less unencumbered than he was the last time. There are no restraints. This is maximum Trump,” he said.

Butts is part of a WhatsApp group with others who staffed heads of state and government during the first Trump term. “Someone joked that the big fear the last time was that he didn’t know what he was doing and the big fear this time is that he does,” he recounted.

Trump allies have long argued that his bluster and most audacious statements are all part of his complex negotiating tactics. Aides note that nearly half of U.S. shipping containers travel through the Panama Canal and that key canal ports are controlled by a Hong Kong-based firm.

Greenland is home to the Pituffik Space Base, the northernmost US post, which plays a key role in missile warnings and space surveillance. And China and Russia have been making their own investments in the Arctic at a time when new potential shipping routes are opening as ice caps melt.

Canada, Trump's team notes, spends far less on defense than its southern neighbor.

“Every decision President Trump makes is in the best interest of the United States and the American people. That’s why President Trump has called attention to legitimate national security and economic concerns regarding Canada, Greenland and Panama," said Trump-Vance Transition spokesperson Karoline Leavitt.

But Michael McFaul, the Obama-era ambassador to Russia who now serves as director of the Freeman Spogli Institute for International Studies at Stanford University and a senior fellow at the Hoover Institution, said Trump's language is counterproductive to U.S. national security interests.

“President Trump is about to take over at one of the most dangerous times in American history," he said. "We will be best at addressing those threats with allies. Allies are our superpower. And so I wish he would focus on the real threats and not invent threats.”

Trump's trolling is not the negotiating ploy of “crazy genius,” he said, and will have consequences.

“We’ve got serious enemies and adversaries in the world, and we're better off with the Canadians and the Danes with us than pissed off with us," he said.

Indeed, Canadian officials have responded with increasing anger.

“The joke is over,” Dominic LeBlanc, the country’s finance minister and point person for U.S.-Canada relations, said Wednesday. “It’s a way for him, I think, to sow confusion, to agitate people, to create chaos knowing this will never happen."

Mexican President Claudia Sheinbaum responded with sarcasm Wednesday to another Trump proposal: to rename the Gulf of Mexico as the “Gulf of America." Standing before an old map, she quipped that North America should be renamed “América Mexicana,” or “Mexican America,” because a founding document dating from 1814 that preceded Mexico’s constitution referred to it that way.

“That sounds nice, no?” she said.

Denmark and Panama have responded similarly, with Panama's foreign minister, Javier Martínez-Acha, saying, “The sovereignty of our canal," which the country has controlled for more than 25 years, “is not negotiable and is part of our history of struggle and an irreversible conquest.”

Mike O’Hanlon, a senior fellow at the Brookings Institution, said he has been surprised by Trump's recent comments given his previous relative disinterest in using force.

While Trump boasted that he had a bigger and more powerful “nuclear button” than North Korea and bombed Iranian general Qassim Soleimani during his first term, he also cast himself during the campaign as a president who had started no new wars and who would be able to prevent World War III.

O’Hanlon noted that NATO members are sworn to defend each other if they are attacked, creating what would be an unprecedented situation were Trump to actually try to forcefully take Greenland.

“You could make a strong argument that the rest of NATO would be obliged to come to Denmark’s defense," he said. “It does raise the possibility, at whatever crazy level, of direct military force.”