Committee Republicans asked the Justice Department to appoint another special counsel back in July, and appeared frustrated that it hasn’t happened yet. “It sure looks like a major political party was working with the federal government” to gin up a dossier and get the F.B.I. to “spy on Americans associated with President Trump’s campaign,” Representative Jim Jordan of Ohio said. “Doesn’t that warrant naming a second special counsel?”

To his credit, Mr. Sessions did not take the bait. “‘Looks like’ is not enough basis to appoint a special counsel,” he said. But, in a letter on Monday, his department told the committee that it was weighing such a move.

Whether or not the department appoints a special counsel, the pressure to do so is clear, from both Republicans in Congress and Mr. Trump, who has threatened Mr. Sessions’s job if he fails to prosecute Mrs. Clinton. That’s what’s so alarming: the push for the Justice Department to undertake a politically motivated investigation of a president’s political opponent, and purely as revenge for an actual investigation already underway.

Meanwhile, Mr. Sessions spent most of Tuesday’s hearing as he has all the others he’s sat through this year — by not recalling things that one would think most people would. At his confirmation hearing in January, he testified that he’d had no contact with Russians during the 2016 presidential campaign. Turns out he met at least twice with the Russian ambassador, Sergey Kislyak. Last month, Mr. Sessions appeared before the Senate again and was asked if any Trump campaign surrogates had had communications with the Russians. “I did not, and I’m not aware of anyone else that did, and I don’t believe it happened,” he said. Wrong again: Mr. Sessions spoke with at least two members of the Trump campaign, Carter Page and George Papadopoulos, about their plans to travel to Russia, where, Mr. Papadopoulos said, he would meet with government officials.