He remains the most powerful person in the world, yet he is focused on the one area in which he is powerless to get what he wants: a way to avoid leaving office as a loser.

He spends his days flailing for any hope, if not of actually reversing the outcome of the election then at least of building a coherent case that he was robbed of a second term…

For the moment, Mr. Trump has told advisers he’s willing to stop listening to Sidney Powell, the lawyer who has appealed to him by peddling a conspiracy theory about the election, and people like Patrick Byrne, the former chief executive of Overstock.com, who was present for a wild, nearly five-hour meeting in the Oval Office and then the presidential residence last Friday.

But current advisers have described a daily struggle to keep Mr. Trump from giving in to his impulse to listen to those who are telling him what he wants to hear. And former advisers say the most worrisome issue is the gradual disappearance of the core group of West Wing aides who, often working in unison, consistently could get him to turn away from risky, legally dubious and dangerous ideas.