Mr. Gordon has said Mr. Sessions “shut down” the discussion. He said on Monday that he stood by his account.

“I don’t have anything to add to my numerous TV interviews on the subject last year,” Mr. Gordon wrote in an email, linking to one in which he said that “Senator Sessions shut down that discussion because it was a bad idea, and he said, ‘I prefer if no one ever speaks about this again.’”

Democrats have remained mum about the new account contradicting Mr. Sessions’s testimony, itself a sign of how unusual his tenure has been.

Mr. Sessions’s recusal from election-related investigations has made him the linchpin in a balancing act within the Justice Department around Robert S. Mueller III, the special counsel investigating whether the Trump campaign conspired with Russia’s interference in the presidential race. Rod J. Rosenstein, the deputy attorney general, oversees Mr. Mueller’s inquiry and has publicly backed it.

Mr. Trump has made plain his displeasure with Mr. Sessions and has signaled that he could fire him after the midterm elections. Mr. Trump could replace him with an interim attorney general who would at least temporarily not be subject to Senate confirmation and could take back oversight of the special counsel investigation and move to end or at least slow it, moves Democrats adamantly oppose.

Republican allies who stood with Mr. Sessions amid months of criticisms from the president have also begun to distance themselves. Senator Lindsey Graham, Republican of South Carolina, said recently that he expected the attorney general to be fired “sooner rather than later,” and that Mr. Trump was entitled to make such a move.

And Senator Charles E. Grassley, Republican of Iowa and the powerful head of the Senate Judiciary Committee, said he would be willing to hold confirmation hearings for a new attorney general, after maintaining for months that he would not help find a replacement if Mr. Trump ousted Mr. Sessions.