Negotiations seemed to be progressing in May, when officials announced that they had agreed on a framework that would see China increase its purchase of American goods and services to reduce a trade imbalance between the countries. But that consensus quickly evaporated, as Mr. Trump was criticized for being soft on China and the White House ramped up its tariff threats.

China has expressed frustration that the United States has not established a clear point person in the negotiations, which have been led by an alternating group of officials including Steven Mnuchin, the Treasury secretary; Robert E. Lighthizer, the United States trade representative; Mr. Ross; and others. This week, the Treasury Department designated David Malpass, the under secretary for international affairs, to lead the discussions.

While the Trump administration has outlined its broad priorities, the specifics of its demands remain murky and China continues to meet every new tariff threat with its own promise of retaliation.

“I’m not particularly optimistic that we’re going to see a deal anytime soon,” said David Loevinger, the Treasury Department’s senior coordinator for China from 2009 to 2012. “It’s still kind of unclear what it would take for the U.S. to get to yes on a trade deal.”

Also unclear is whether the tariffs and investment restrictions have done much to persuade China to make further concessions on trade, beyond its offers this year to purchase American goods and open up some markets to more foreign competition. Some Chinese officials now appear to suspect that Mr. Trump’s trade plans are part of a broader effort aimed at thwarting China’s rise, and that any concessions would do little to prevent what looks like an intensifying struggle for global dominance between the countries.

At a campaign rally in West Virginia on Tuesday, Mr. Trump lauded his success in slowing China’s rise.

“When I came, we were heading in a certain direction that was going to allow China to be bigger than us in a very short period of time,” Mr. Trump said. “That’s not going to happen anymore.”