As they have throughout the week, the House managers spotlighted the president’s efforts to conceal his abuse — and how he’s still at it. Message to all the folks watching at home: There is still so much out there that we don’t know! Pressure your senators to subpoena key witnesses and documents!! Attention must be paid!!

Indeed, away from the Senate floor, the tussle over whether to pursue fresh evidence has continued. Recent polls show that a sizable majority of Americans think additional witnesses should be called at the trial. Of course, the iron-fisted majority leader, Mitch McConnell, is not among them, and he has been working hard to keep the troops in line. At a closed-door lunch Wednesday, Senate Republicans received a briefing about how tedious and time consuming it could be to wrest information from the White House. Republican lawmakers increasingly are fretting that, if the Senate starts issuing subpoenas, the president would just claim executive privilege, miring the fight in the courts and dragging it out for months.

“The House made a decision that they didn’t want to slow things down by having to go through the courts,” Senator Lisa Murkowski, the Alaska Republican, told CNN Thursday. “And yet now they’re basically saying you guys got to go through the courts. We didn’t, but we need you to.”

Ms. Murkowski is considered one of the Republicans most open to voting for new witnesses.

Small wonder some Democrats are feeling anxious. “I was much more optimistic last week than I am this week about winning the vote on witnesses,” Senator Chris Murphy, a Connecticut Democrat, told Politico. “I thought by this week there would be a critical mass of Republicans.”

Mr. Trump kept the pressure on as well. During his morning “executive time” Friday, the president tweeted precisely the sort of statesmanlike commentary we’ve come to expect, rich with name-calling, all-caps ranting (“READ THE TRANSCRIPTS!”) and mewling about process. He expressed particular irritation that the House managers “want to use up ALL of their time, even though it is the wrong thing to do.”