Still, for the worst impeachment moment, I’m going with Susan Collins. The idea that Donald Trump had learned any lesson is ridiculous. Collins knows — the whole world knows — that Trump is a man with a learning curve that resembles a garter snake.

On the same day she delivered her theory as an excuse for voting for acquittal, the president discussed his Ukraine-related behavior at a lunch with television anchors. What do you think he said?

A) “All of life is a learning process.”

B) “Maybe I might concede I could possibly have done a little better.”

C) “It was a perfect call.”

Yeah, it’s C. You do know your president, don’t you?

Collins had made a splash by voting in favor of calling witnesses during the Senate’s impeachment trial. We live in times when agreeing to listen to people who know a lot about the matter you’re debating is an act of extreme daring.

Of course, the witness thing failed. Some dark minds believe that Collins’s moment of independence came only because McConnell knew he had enough votes to kill the proposal without her. Collins is heading toward a tough re-election in Maine this fall, and she needs bipartisan support. Perhaps, people of Maine, you haven’t noticed that your senator’s political independence tends to work best when the matter at hand is meaningless. Could be worse. At least she respects you enough to pander.