Under Heavy Pressure, Trump Releases Video Condemning Capitol Siege

The president has also left open the possibility of pardoning himself, despite concern from Mr. Cipollone and warnings from outside advisers that he would inflame investigators who are already pursuing him.

Mr. Trump has never been more isolated than this week. The White House is sparsely staffed, according to people who went to work there on Wednesday. Those who did go to work tried to avoid the Oval Office.

More and more staff members have quit, and the White House Counsel’s Office is not preparing to defend him in the Senate trial. His political adviser, Jason Miller, posted on Twitter a poll from one of the campaign’s pollsters, John McLaughlin, that was intended to show the president’s grip on the party, as House Republicans debated their votes.

Plans to move Mr. Trump to another platform online after he was barred by Twitter have been halted. One option was the platform Gab, which has drawn extremists and QAnon conspiracy followers. Mr. Trump’s adviser Johnny McEntee favored the site, but Mr. Kushner blocked the move, according to people familiar with the discussions, which were reported earlier by Bloomberg News.

Mr. Giuliani is among those facing recriminations because of their involvement in inciting the mob that assaulted the Capitol. A group of former assistant U.S. attorneys who worked with him when he served as a federal prosecutor in Manhattan expressed dismay on Wednesday with his appearance at the rally beforehand.

In a letter, the group said that Mr. Giuliani’s comments, in which he urged Trump supporters to engage in “trial by combat” to stop the certification of the election results, contributed to the loss of life and inflicted damage on the country.

“It was jarring and totally disheartening to have seen one of our former colleagues engage in that conduct,” the former prosecutors said in the letter, which was signed by many Giuliani colleagues, including Kenneth Feinberg, Ira Lee Sorkin, Elliot Sagor and Richard Ben-Veniste.