Having campaigned on a policy of ending wars, making peace, putting America first and disentangling the country from the world, President-elect Donald Trump this week decided to revive 19th-century imperialism. In a single news conference, he pondered making Canada a state and acquiring Greenland and the Panama Canal by economic coercion — and declined to rule out using military force in the latter two cases. Republican leaders, whom Trump has only recently trained to denounce their party’s old foreign policy of expansionism and internationalism, quickly pivoted again and adopted the new party line, and are now showering praise on Trump’s grand vision and big thinking. Where will all this go?

Some say we are simply back to the “madman theory” of foreign policy, which posits that it’s good for the president to sometimes appear unpredictable, even irrational, because it throws adversaries off guard. It’s worth recalling that Trump tried this gambit in his first term, most obviously with North Korea’s Kim Jong Un. None of it worked.

The scholar Daniel W. Drezner notes that much research has concluded that the originator of the madman theory, Richard M. Nixon, produced no positive results for his efforts to seem crazy and unhinged.

The talk about making Canada a state appears to be mostly trolling, targeted at that country’s liberal prime minister, whom Trump dislikes. But it has forced even Trumpian politicians to firmly push back. Trump might be encouraging greater anti-Americanism in Canada.

Trump’s focus on Panama and Greenland has some basis. The Panama Canal is one of the world’s great maritime choke points. But the Panamanian authorities have managed it responsibly, professionally and in no way treated the United States badly — as even the Wall Street Journal Editorial Board recently noted.

Greenland is turning into a pivotal place, largely because of climate change (which, ironically, Trump has called a “hoax”). The melting of the polar ice caps will open up new oceanic shipping routes between Europe and North America, and Russia and China will actively try to gain influence in these new seaways. It is — and should be — American policy to thwart both nations’ efforts to expand their economic and military footprint here.

But the United States doesn’t need to acquire Greenland to do this. It already has all the access to the island it wants. Washington had a string of bases on the island during World War II and the Cold War. One remains and is now operated by the Space Force.

In fact, Denmark has actively assisted in America’s newfound interest in Greenland. A few years ago, Greenland (which is governed semi-autonomously) nearly made a deal to accept Chinese financing for a set of new airports. The Pentagon asked Denmark to prevail on the Greenlanders to cancel the deal. The Danish government succeeded, replacing much of the Chinese financing with its own. Working with Denmark made America’s efforts more effective.

America has been so influential around the world because it has been able to persuade others that it seeks to act not just in its narrow self-interest but for broader interests — that it wants peace, stability, rules and norms that help everyone.

That’s why it was able to get 87 countries to immediately condemn Russia’s war of aggression against Ukraine. That is why so many of China’s neighbors have allied themselves with the United States.

In the news conference, Trump proposed getting rid of the “artificially drawn line” between Canada and the United States. Of course, that is precisely what President Vladimir Putin says about the line between Russia and Ukraine. Or President Xi Jinping about the division between China and Taiwan. This is a world that makes Russia and China great again.

Email: fareed.zakaria.gps@turner.com.