Mr. Trump signaled some of that impatience on Tuesday when, writing on Twitter, he gave marching orders to the Democrat-controlled House, which returns from its summer recess next week. The House should move on from “witch hunt” investigations, he wrote, and “get back to work on drug prices, health care, infrastructure and all else.”

But on two of those three issues, Mr. Trump has sent mixed signals about his willingness to actually negotiate. Mr. Trump called action on infrastructure “a necessity” during his State of the Union address in February, yet he angrily canceled a meeting on the subject with Democratic leaders in May after learning that Speaker Nancy Pelosi had suggested he was engaged in a “cover-up,” and talks ground to a halt.

Nor has Mr. Trump backed up his talk of action on health care. The president has said he will submit to Congress a health care plan to completely replace President Barack Obama’s Affordable Care Act, and told ABC News in mid-June that he would do so “in about two months, maybe less.” More than two months later, he has not done so, and many Republicans are skeptical that he ever will.