Impeachment during the primaries creates multiple problems for Democrats. One is that it underscores, regardless of the disclaimers, the essentially political nature of this impeachment. The fact is, Democrats are impeaching the president in an election year with the goal of rendering him unelectable against the Democratic candidate. It doesn’t get more political than that.

Then there is the practical problem impeachment creates for Democratic presidential candidates. At the moment, there are six Democratic senators running for president. Presumably some will drop out by next February. But it seems likely that other senators, like top contenders Elizabeth Warren and Bernie Sanders, will still be in the running. Instead of campaigning, though, they will be chained to their desks in the Senate chamber in Washington for the duration of a Senate impeachment trial. That’s not the best way for a candidate to spend the weeks leading up to caucuses and primaries.

The other reason for the Democratic rush is the potential for impeachment fatigue. Some recent polls have shown public support for impeachment leveling off and even tipping downward.