That this IS a partisan question is an object lesson in why the 2-party system is bad – that the question of partisan advantage over its TIMING is a serious concern for Democrats is an indication that the 2-party system is BROKEN. Trump is not a Republican in anything but the technical sense. His divisive politics; his disregard for the law; his contempt for reason, science, & faith in equal measure; his venal narcissism, his reductionist worldview rife with misinformation and nonsense – any of these traits are obvious to anyone willing to appraise him honestly, and each is sufficiently disqualifying on its own. That evidence also mounts weekly indicating he committed acts of treason to secure his current office, and has sought repeatedly to prevent investigations into his behavior are icing on that cake, and unnecessary as far as determining grounds for impeachment.
This man and those who serve him are an existential threat to the survival of this nation. Removing him from office is not sufficient, but it is a necessary first step, & any short-term concerns about the partisan political cost of taking that step are misplaced. The Republican Party has failed repeatedly to place the needs of the country above their party when it came to the threat this man posed, and they will suffer for it – if Trump is successfully removed from office it will likely mean the end of their party as it currently exists, either through organic infighting or because Trump himself brings it about.
But Trump is the apotheosis of the corruption that has infected the American system for decades, and the things that make him a threat are not inherently conservative. If Democrats make the mistake of prioritizing their group over the needs of the greater whole, they prove they are also not worth preserving, and we would be better served destroying both parties together, and building new political structures to manage ideological differences. The Constitution does not demand parties at all, and even if we have them, it does not require only two.
Any long-lived institution will naturally seek its own perpetuation. Such self-preservative instincts are perfectly fine – even beneficial – so long as they also provide symbiotic benefit to the society of which they are part. But when that relationship becomes more parasitic, and those self-preservative moves become actively hostile to the society’s own survival, the sane response for that culture is to dismantle the infecting institution.