White House officials are universally angry with Mr. Giuliani and blame him for both of Mr. Trump’s impeachments. But the president is another story.

Even as he complains about Mr. Giuliani’s latest efforts as fruitless, the president remains unusually deferential to him in public and in private. “Don’t underestimate him,” Mr. Trump has told advisers…

Mr. Trump deployed Mr. Giuliani on politically ruinous missions that led to his impeachment — twice. Now, isolated and stripped of his usual political megaphones, the president faces the devastation of his business and political affairs for his part in encouraging a pro-Trump mob that went on to attack the Capitol on Jan. 6.

Mr. Giuliani — who, for his part, encouraged a group of the president’s supporters that day to carry out “trial by combat” — is one of few people still willing and eager to join Mr. Trump in the foxhole. While most lawyers are reluctant to represent the president in a second Senate impeachment trial, Trump advisers said Mr. Giuliani remained the likeliest to be involved. Despite President-elect Joseph R. Biden Jr.’s certification as the winner, Mr. Giuliani has continued to push unproven theories about the election results and falsely attributed the violence to anarchists on the left.