When Donald J. Trump championed the idea of a 10 percent blanket tariff during the campaign, many people, whether for or against, were taken aback by how radical the idea was.

Alarms sounded about higher inflation, lost jobs, slower growth or recession. The prospect seemed so outlandish that most economists and Wall Street analysts who gamed out the possibilities tended to treat a 10 percent tariff simply as a bargaining tool.

Now, after a rapid-fire series of announcements from the White House that promised, imposed, reversed, delayed, decreased and increased tariffs, the 10 percent solution is looking like the most temperate choice rather than the most revolutionary, especially now that a red-hot trade war between China and the United States is blazing.

Yet 10 percent tariffs have not lost their sting.

At that level, universal tariffs still hit more than 10 times as many imports as the ones targeted during Mr. Trump’s first term, and are significantly higher and broader than anything the United States has tried in more than 90 years.

The tariff rate is “quite extreme,” said Carsten Brzeski, chief eurozone economist at ING, a Dutch bank. “It still brings us back to levels last seen during the 1930s.”

In addition to measures targeting China, Mr. Trump powered up a long list of punishing taxes — including a flat 10 percent tariff on most imports — on April 9.