Harris’s idea that the party can simply run these investigations, uncover damaging evidence, and then—presumably—move on to other scandals is simply not plausible. The party’s base is fed up and insistent that Democrats “do something” about Trump and his cronies, which is to say that people want to see them stopped and punished. It’s hard to imagine that investigations alone will be enough to satisfy this bloodlust, even if Democratic voters know that there is no chance of convicting and removing Trump.
https://newrepublic.com/article/217316/democrats-trump-impeachment-party-base-no-choice
I think this response to Harris is interesting.