While perhaps emotionally satisfying, impeachment would have little practical use. There is the constitutional duty of House members to investigate what seem to be obvious criminal acts by the president, but knowing impeachment will inevitably end in acquittal and will almost certainly bolster Trump’s support in the 2020 render impeachment an exercise in pointlessness. Prosecutors routinely decline to pursue cases they can’t win (even if the defendant is plainly guilty).

The argument that “taking the case to the people” will somehow make clear to voters qualities that are yet obscure, thereby affecting the chances that the Senate would judge Trump guilty if evidence is persuasive, strikes me as wishful thinking. The Mueller report is right there for everyone to read, and the WH and Barr are quite publicly breaking the law at Trump’s request by not obeying subpoenas (more obstruction). If voters don’t see what Trump is by now, I doubt anything more will turn up in an impeachment investigation that the WH will also continue to refuse to cooperate with.

Good reasons exist to think Trump and the Republicans want the Democrats in the House to pursue impeachment and are engaged in a campaign to pressure them into doing that.

Another argument I’ve encountered is that impeachment would be a statement, a kind of last stand against the erosion of civil norms and Trump’s flouting of the law, along the lines of “we refuse to give into the dictatorial undermining of our democracy so we are going to do our legal duties, regardless of the outcome.” This is a nice idea, but sadly, the damage to our democracy has already been done if the flagrancy of such criminal behavior is not sufficient for the Senate Republicans to convict.