SINGAPORE — President Trump’s eager embrace of Kim Jong-un of North Korea this week, on the heels of an acrid falling-out with Prime Minister Justin Trudeau of Canada, raised an obvious, if confounding, question: Why would an American president offend allies and cozy up to adversaries?
If there was an answer in Mr. Trump’s tumultuous week on the global stage, it may be that he disregards the traditional preoccupations of American foreign policy — power and values — in favor of a more narrow worldview shaped by his experience as a businessman.
“The theme that comes up, over and over, is money,” said Jeffrey A. Bader, a diplomat who advised President Barack Obama on China.
Mr. Trump’s bitter clashes with Canada and Europe over trade, as well as his solicitous courtship of North Korea’s brutal dictator, all reflect this mercantile perspective. In his transactional approach to foreign policy, considerations of financial profit or cost — often measured in ways that economists deem simplistic — can outweigh virtually any other consideration.
“What that means is that Trump, like a lot of businessmen, doesn’t pay much attention to Canada, or Europe, or Japan,” Mr. Bader said. “Businessmen pay attention to the growth markets: Vietnam, Brazil, India, China.”
Or, as was on vivid display in Singapore this week, North Korea.
That does not mean Mr. Trump is necessarily interested in North Korea as a trade partner or an investment opportunity for the United States. But his view of the challenges posed by the Korean Peninsula are colored — and perhaps limited — by his background in business.
In Mr. Trump’s meetings with Mr. Kim — the first for a sitting president and a North Korean leader — he soft-pedaled traditional American concerns like regional security and human rights. Instead, he celebrated North Korea’s economic potential and pitched Mr. Kim like a property developer proposing to build condominiums on a reclaimed Superfund site.
A slick promotional video that Mr. Trump showed Mr. Kim sketched out a gleaming vision of a prosperous, nuclear-free North Korea, with swooping construction cranes and high-speed trains. Though it also framed the life-or-death nature of North Korea’s nuclear showdown with the United States, the four-minute film had the inspirational tone of a Chamber of Commerce testimonial.
”They have great beaches,” Mr. Trump said to reporters. “You see that whenever they’re exploding their cannons into the ocean, right? I said, ‘Boy, look at the view. Wouldn’t that make a great condo behind?’ And I explained, I said, ‘You know, instead of doing that, you could have the best hotels in the world right there.’”
North Korea may consider its position between China and South Korea, with Japan across the water, as reason to be worried about military security. But Mr. Trump considers it a prime location amid booming economies. “Think of it from a real-estate perspective,” he said.
Mr. Trump brought a similarly bottom-line view to the 28,500 American troops stationed in South Korea, as well as to the military exercises the United States conducts with the South. He reiterated his desire to bring the troops home and announced he was halting the exercises — much to the surprise of the Pentagon and the South Korean government, neither of which had been warned.
“We save a fortune by not doing war games, as long as we are negotiating in good faith — which both sides are!” Mr. Trump said on Twitter.
The president expressed particular spite at the B-52 bombers that the United States has flown over South Korea in missions from Guam. These planes, which can carry nuclear weapons, are a potent manifestation of the American commitment to protect its Asian allies. But to Mr. Trump, they burn a lot of fuel and serve little purpose circling in the skies over the Korean Peninsula.
“I know a lot about airplanes,” he said. “It’s very expensive.”
Mr. Trump’s sense of economic injustice runs even deeper when it comes to Canada and the European Union. Asked on Tuesday about his clash with Mr. Trudeau after the Group of 7 meeting in Quebec, he answered with a long list of grievances — some based on erroneous data — about the trade deficits the United States runs with Canada, Germany, and other allies.
“We are being taken advantage of by virtually every one of those countries,” Mr. Trump said. “They don’t take our agricultural products, barely. They don’t take a lot of what we have and yet they send Mercedes into us. They send BMWs into us by the millions. It’s very unfair.”
The president made no reference to the wars that Canada and European allies have fought alongside the United States; the counterterrorism operations they have coordinated; the world trade system they have managed together; or the democratic political systems and respect for human rights that they share. If anything, experts said, this common history is a red flag to Mr. Trump.
“A consistent theme of the Trump administration has been to downgrade the value of allies and alliances,” said Richard N. Haass, the president of the Council on Foreign Relations. “To the contrary, they tend to be judged as military free-riders or economic rivals or both. That many are assertive, independent-minded liberals that regularly challenge the president only makes it worse.”
Officials in Japan and South Korea have been more reluctant than those in Europe or Canada to push back against Mr. Trump. But analysts in Asia said his comments in Singapore about withdrawing troops and canceling the joint military exercises left both countries rattled.
The widening fissures in America’s Pacific and Atlantic alliances, experts said, carry implications that go beyond bruised feelings or potential trade wars. In his single-minded focus on economic gain, sometimes poorly defined, critics say Mr. Trump risks undermining an international order built by the United States to bolster American security and values as well as prosperity.
In Europe, Russia could feel emboldened to bully its neighbors, confident that a divided West will do little to stop it. In Asia, the fraying of the America’s nuclear umbrella could encourage China to increase its military adventurism in the South China Sea.
The paradox of Mr. Trump’s transactional approach to statecraft is that the joint statement he signed with North Korea looks like the kind of deal he once derided. It does not commit the North to the complete, verifiable and irreversible denuclearization that his administration has long demanded. It does not address the North’s fleet of ballistic missiles. It does not even set a deadline for next steps.
“The bottom line,” said Daniel R. Russel, a former assistant secretary of state for East Asian affairs now at the Asia Society, “is that President Trump paid retail for a few warmed-over promises and appears to have given away both leverage and deterrence.”
Or, as Mr. Haass put it in a tweet on Tuesday, “The containment doctrine has given way to the condominium doctrine.”