The latest stock market bump could give the president comfort that he can continue waging his fights with two of America’s largest trading partners — China and Mexico — without derailing the economic recovery.

Mr. Trump, speaking in London on Tuesday, said he was ready to punish Mexico with tariffs next week for failing to curb the flow of migrants across the southern border.

“I think it’s more likely that the tariffs go on, and we’ll probably be talking during the time that the tariffs are on, and they’re going to be paid,” Mr. Trump said. The president has threatened to increase those tariffs to 25 percent by October, a move that could hurt the North American economy.

Investors, bond markets and Wall Street analysts have grown increasingly alarmed by the potential slowdown in growth that could result from Mr. Trump’s tariffs on China and Mexico. The worsening outlook for trade over the past month has been accompanied by signs of weakness in global markets. Prices of key industrial commodities such as crude oil and copper have slipped.

After hitting a high on April 30, the S&P 500 was down nearly 7 percent through the close of trading on Monday. Yields on safe government bonds had tumbled worldwide. And yields on some long-term Treasury securities are now below those of short-term bills, an unusual occurrence known as an “inversion of the yield curve,” which, in the past, has heralded recession.

Against that backdrop, investors have grown increasingly expectant that the Fed will abandon its “patient” stance and move to cut interest rates in the coming months. Fed funds futures markets are now placing a probability of more than 60 percent on the Fed reducing interest rates at its meeting at the end of July, according to Bloomberg data. Earlier in May, the market was putting less than 20 percent odds on such a move.

Taken with his colleagues’ recent statements, Mr. Powell’s speech signals that the Fed is not yet ready to lock in coming rate cuts. Robert S. Kaplan, the president of the Federal Reserve Bank of Dallas, said in an interview that he still favored patience on rates, especially because at least some of the trade tensions might be resolved.