But the involvement of Mr. Giuliani, who held a widely mocked news conference in front of a landscaping company in Philadelphia last weekend in which he claimed widespread fraud, has vexed people on the campaign and in the White House.

A half-dozen other Trump advisers have described Mr. Giuliani’s efforts as counterproductive and said that he was giving the president unwarranted optimism about what could happen. Those advisers have said that they are concerned Mr. Giuliani is damaging not only Mr. Trump’s remaining legal options, but his legacy and his future opportunities in politics as he considers another campaign in 2024…

In an Oval Office meeting with aides on Thursday, Mr. Trump put Mr. Giuliani on speakerphone so the others could hear him. He angrily accused the aides of not telling the president the truth, according to people briefed on the meeting. Justin Clark, the deputy campaign manager, pushed back aggressively on Mr. Giuliani, said the people briefed on what took place.