It came at the end of a quarter in which stock prices were down sharply, Wall Street’s worst performance at the start of a new presidential term since Gerald R. Ford tried to steer the country out of scandal and inflation 51 years ago. And it only added to the widespread uncertainty among businesses and consumers about what the rest of the year might hold as Mr. Trump pursues a trade war that is already choking off supply chains and threatening to push prices up and lead to shortages of critical components and products on shelves.

It is too soon to predict where the American economy is headed for the rest of the year, and Mr. Trump remains insistent that he will produce a flurry of trade deals that will bring manufacturing back to the United States and usher in a new age of prosperity.

But the first-quarter figures brought the political risks for him into focus. For Mr. Trump, what is at stake is a question of fundamental competence on an issue that he has always used to define himself.

If the report proves to be a harbinger of an extended slowdown or recession, the situation could become the economic analog of President Joseph R. Biden Jr.’s fumbled withdrawal from Afghanistan four years ago this summer. Mr. Biden’s job approval ratings never recovered from that early debacle. Nothing he did later — not the millions of jobs created, not the big legislative victories, not the rapid response to Russia’s invasion of Ukraine — could restore the sense among voters that he could be trusted to carry out the job with the skill they assumed he brought to it.

Mr. Trump stood in the Rose Garden on April 2, what he called “liberation day,” and rolled out a broad and punitive set of tariffs on trading partners. He has promised that other countries will come begging for a deal to roll back those levies and other tariffs he has imposed.

A substantial number of Americans appear skeptical. In a New York Times/Siena College poll last week, 55 percent disapproved of Mr. Trump’s handling of the economy, with 43 percent approving. About half of voters disapproved of Mr. Trump’s handling of trade.

Some of Mr. Trump’s economic advisers now recognize that the timing and execution of his tariff announcements could prove to be colossal mistakes, even if they applaud the underlying strategy. That is why, every few days, they are announcing new exceptions, most recently to relieve the pain for American carmakers.

“On April 2, standing in arguably the most powerful place in the world, President Trump thought he was projecting American strength,” said Matthew P. Goodman, who runs the geoeconomics center at the Council on Foreign Relations and served under Presidents George W. Bush and Barack Obama. “But he discovered that trade is complicated, that you need to be more surgical, and he has had to tack back from that ever since.”

Mr. Trump, the billionaire real estate investor, has acknowledged that his strategy will bring some temporary pain to Americans, but seemed to argue on Wednesday that it would hardly be noticed by ordinary Americans, at least at toy stores.

“Well, maybe the children will have two dolls instead of 30 dolls, you know?” he said. “And maybe the two dolls will cost a couple of bucks more than they would normally.”

Whatever the cost of a Barbie, Mr. Trump is facing a fundamental timing problem. It will take years for the huge investments he predicts will flow into the United States to unfold and bring about the industrial renaissance he has promised. Building the most cutting-edge semiconductor fabrication plant, for example, can easily take five years.

“Those chips, those beautiful chips, make those suckers in the U.S.A.,” Mr. Trump said in the White House on Wednesday as he addressed executives and called out how much each had committed to spending on new facilities in the country.

It is too early to know how quickly those investments will take off, including Apple’s commitment, hailed again by Mr. Trump on Wednesday, to invest $500 billion, including a chunk of its manufacturing capability, in the United States over the next four years.

But the economic pain of the tariffs could start within months, with upward pressure on prices and shortages of both industrial and consumer products made abroad.

Much of Mr. Trump’s political problem lies in that disconnect. For many of the products Americans will be paying more for — especially Chinese-made products — there is no American alternative. And for many more, producing them in the United States may make no sense.

For all his downplaying of economic concerns, Mr. Trump is clearly sensitive to the prospect of being blamed for rising prices. When reports began to circulate this week that an Amazon subsidiary was thinking about posting the tariffs customers would be paying on every product, Mr. Trump called Jeff Bezos, Amazon’s founder, to complain.

Giving consumers a breakdown of how much tariffs are costing them, the White House said, would be a “hostile and political act.” Amazon quickly said it had never fully approved the plan, and that it would not go into effect.

But many business leaders are rattled by the environment, saying they have no way of projecting their earnings for the second quarter because the economic environment has never been more opaque.

“I keep telling them not to underestimate Donald Trump,” said David McIntosh, the president of the Club for Growth, the anti-tax advocacy group whose members almost unanimously cheered Mr. Trump’s return to office.

Mr. McIntosh said he is optimistic that Mr. Trump will be successful at negotiating down tariffs with Western-style democracies that rank among America’s biggest trading partners. “I run into a lot of executives who ask, ‘OK, how does Donald Trump do this?’ And my answer is to wrap their minds around ‘The Art of the Deal,’ that he is negotiator in chief.”

The way to calm the markets now, he said, is to “get Congress to get the tax cut bill done,” and to extend the tax cuts Mr. Trump got enacted in his first term.

Mr. McIntosh is pressing to expand that tax cut, specifically by permitting businesses to write off the cost of building new production facilities immediately, rather than depreciate those costs over decades.

Mr. Trump may score some early wins. Treasury Secretary Scott Bessent said on Tuesday that “we are very close on India.” He added that South Korea was “sending its A-team” to negotiate and that a deal was also possible soon with Japan. Mr. Trump said on Wednesday that Canada’s new prime minister, Mark Carney, had called him the day before and said “‘Let’s make a deal.’”

Perhaps so, but Mr. Carney also had this to say on Tuesday after winning the Canadian election: “Our old relationship with the United States, a relationship based on steadily increasing integration, is over. The system of open global trade anchored by the United States, a system that Canada has relied on since the Second World War, a system that, while not perfect, has helped deliver prosperity for a country for decades, is over.”

Mr. Carney has vowed to reduce Canada’s dependence on its huge neighbor, no easy assignment since bilateral trade amounts to about a fifth of the country’s economy. China, the most powerful player in Mr. Trump’s trade wars, has been pursuing a similar strategy. And its leader, Xi Jinping, has every incentive to make the next few months as politically painful for Mr. Trump as possible.

Mr. Xi has largely maintained radio silence since Mr. Trump announced an escalating set of tariffs on Chinese goods, settling at 145 percent after several angry moves and countermoves with Beijing. That rate is so high that it essentially freezes trade; already there are reports of freighters loaded with goods that are being turned around, so that importers do not have to pay those tariffs.

Mr. Trump’s bet is that Mr. Xi will blink first because the pain for the Chinese economy will be so great that he will have to strike an accommodation that will, over time, allow the United States to get back to something approaching normal. Mr. Xi is betting the opposite: that Mr. Trump has overreached, and can’t withstand bad G.D.P. numbers, rising inflation or plummeting polls.

Only one of them is right.