President Trump’s extensive tariffs have already started to generate a significant amount of money for the federal government, a new source of revenue for a heavily indebted nation that American policymakers may start to rely on.

As part of his quest to reorder the global trading system, Mr. Trump has imposed steep tariffs on America’s trading partners, with the bulk of those set to go into effect on Aug. 7. Even before the latest tariffs kick in, revenue from taxes collected on imported goods has grown dramatically so far this year. Customs duties, along with some excise taxes, generated $152 billion through July, roughly double the $78 billion netted over the same time period last fiscal year, according to Treasury data.

Indeed, Mr. Trump has routinely cited the tariff revenue as evidence that his trade approach, which has sowed uncertainty and begun to increase prices for consumers, is a win for the United States. Members of his administration have argued that the money from the tariffs would help plug the hole created by the broad tax cuts Congress passed last month, which are expected to cost the government at least $3.4 trillion.

“The good news is that Tariffs are bringing Billions of Dollars into the USA!” Mr. Trump said on social media shortly after a weak jobs report showed signs of strain in the labor market.

Over time, analysts expect that the tariffs, if left in place, could be worth more than $2 trillion in additional revenue over the next decade. Economists overwhelmingly hope that doesn’t happen and the United States abandons the new trade barriers. But some acknowledge that such a substantial stream of revenue could end up being hard to quit.