President-elect Trump’s talk of territorial expansion has rattled world leaders at an already precarious time in global politics.

Trump doubled down last week on his suggestions that the U.S. buy Greenland, take control of the Panama Canal and make Canada “the 51st state.” He declined to rule out “military or economic” coercion against either Greenland or the canal, and he said he was open to using “economic force” on America’s neighbor to the north.

Leaders in the targeted regions and elsewhere have pushed back against the suggestions, even as experts are still largely undecided about how much stock to put in Trump’s threats. That kind of guessing game, experts say, isn’t good for global security as Trump heads into his second term.

“Uncertainty is bad in international affairs. You want to know that your allies are with you, and your enemies need to know that you’re resolute against them. … You want to know, more or less, what the world is going to look like in the morning,” said Peter Loge, a political science professor at George Washington University and a senior FDA adviser during the Obama administration.

Some have guessed that Trump is just trolling as he gets ready to retake the White House later this month. Others have said they think the president-elect’s comments at his Florida presser last week suggest a potential shift away from jokes and toward a more serious aim of American territorial expansion, though he hasn’t yet shared any specifics on his proposals.

“In diplomacy, language matters and signaling matters. And when you're dealing with someone as erratic as Trump is, that’s a problem, if you can't distinguish between the insult comic dog and an actual U.S. foreign policy,” said Duane Bratt, a political science professor at Mount Royal University in Calgary, Alberta, with a focus on Canadian foreign policy.

Whether or not Trump’s serious, it’s obligating global leaders to respond as if he is.

Canadian Prime Minister Justin Trudeau — whom Trump has labeled “governor” — hit back that “there isn’t a snowball’s chance in hell” that Canada would become part of the U.S. On Thursday, he quipped to CNN that one of Canadians’ defining traits is that they’re “not American” and dismissed the threats as a distraction from Trump’s proposed 25 percent tariffs.

Canadian Finance Minister Dominic LeBlanc

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