Mr. Navarro is now one of the few remaining advocates of a nationalist trade policy following the departures over the summer of Reince Priebus, Mr. Trump’s first chief of staff, and Stephen K. Bannon, the chief strategist. Stephen Miller, Mr. Trump’s senior adviser, and Mr. Lighthizer are now Mr. Navarro’s primary allies on trade. Commerce Secretary Wilbur Ross has also been an ally, particularly in pushing for tougher steel import restrictions.

The power of the pro-trade advocates inside the White House suggests a willingness by Mr. Trump to back away — at least temporarily — from some of his harshest rhetoric from the campaign trail. They appear to have successfully convinced the president that trade deals can be used as leverage in broader conflicts with nations like North Korea and Mexico. Ripping them up would mean losing that potential advantage, the trade advocates have argued.

White House officials say Mr. Trump still remains committed to ending trade agreements if they can’t be renegotiated to his liking. But they say he has recognized that there is a need for a more considered approach as he is confronted by other domestic and international issues — like North Korea, illegal immigration and drug trafficking on the border with Mexico.

Mr. Lighthizer has advanced a series of far-reaching proposals to revise Nafta that are backed by Mr. Navarro and Mr. Ross. But Canadian and Mexican counterparts, as well as business groups, object to the provisions as non-starters. On Tuesday, the parties postponed the next round of talks until next month to give negotiators more time.

Mr. Navarro would have preferred a more aggressive approach, officials said. A former Democratic candidate for San Diego mayor, a Ph.D. economist and a professor at the University of California, Irvine, he has views on trade that diverge with those of most economists, who generally agree that Americans are better off under Nafta. Mr. Navarro criticizes trade deals and trade deficits, saying the Nafta agreement would be more properly called “Shafta.”

In January, Mr. Navarro arrived at the White House with an already written order to ditch Nafta. Although it would not have ended the trade deal immediately, it allowed time to negotiate a better pact or withdraw by the end of 2017. Mr. Cohn objected to the move.