“We already had a tight economy, and then you add fiscal stimulus, and then you add on top of that trade protections,” said Torsten Slok, chief international economist for Deutsche Bank. “It’s close to the perfect storm coming together with these risks of overheating.”

So far, the threat remains hypothetical. Inflation has crept up but remains below the Fed’s 2 percent target, and wage growth remains anemic — even the surprising figure for January was later revised down. If inflation does pick up, it will not result in a recession overnight.

The impact of a potential trade war is harder to assess. The tariffs announced by Mr. Trump so far are small and unlikely to have much effect on the overall economy. But if he pursues broad-based tariffs against China — something he is reportedly considering — and prompts retaliation by the European Union or other trading partners, the consequences could be much greater.

“We know from history that’s lose-lose,” said Adam Posen, president of the Peterson Institute for International Economics, a pro-trade think tank. “It reverberates throughout the U.S. economy.”

Beyond the issue of trade, most experts see few threats likely to derail the recovery in the short term. That is partly because it would take a fairly substantial shock to knock the economy off course. Tax cuts and spending increases may raise the specter of inflation, but they also provide extra insulation against such a shock. Economists surveyed by The Wall Street Journal recently put the odds of a recession in the next year at 14 percent.

“I think we’re going to go gangbusters for the rest of this year,” said Martin N. Baily, who served as chairman of the Council of Economic Advisers under President Bill Clinton and is now an economist at the Brookings Institution.

Economists are famously terrible at predicting recessions. Few saw the last one coming. And although the current expansion has been durable, it has not been particularly strong. Quarterly annualized growth in gross domestic product has averaged just 2.2 percent since the recession ended, compared with 5 percent for the typical recovery since 1950. The economy has basically experienced a long smolder rather than the kind of rapid conflagration common in the past.