The exuberance that spread yesterday across Wall Street after President Trump dialed down his expansive tariffs did not last long. The U.S. stock market fell sharply today, with the S&P 500 down 3.5 percent.

The mood shift highlighted the worries that many investors and economists still have about Trump’s tariff policies. The White House clarified today that imports of Chinese goods now face a 145 percent fee — 20 percent larger than it was understood last night.

It was the latest in a dizzying escalation of tariffs that has unraveled the trade relationship between the two countries and threatened to drag down the world economy. The levies on China could deal a particularly hard blow to American farmers.

“I’ve seen some estimates saying that the impact of the most recent tariff structure is actually worse for consumers, because most of the world’s cellphones, laptops, toys, video games, blankets and party decorations come from China,” our trade reporter, Ana Swanson, told me. “And then, of course, we have the threat of more tariffs hanging over the world after 90 days.”

In addition, the president of the Chicago Fed warned that Trump’s decision to keep in place a universal 10 percent tariff would “materially increase inflation” — dampening today’s encouraging consumer price report.