Sane/Non-Trumpist Republicans - why are you still Republicans?

[Virginiá]

There is nothing wrong or unusual about a reasonable, sane Republican wanting to stick around to hopefully turn their party around at some point. Frankly Democrats need those people to stick around and fight the capture of their party by loons bent on disruption and most definitely not any semblance of governing. America's system as it stands now still needs at least two viable major parties to have some semblance of a functional democracy with a healthy competition of ideas. And of course there is the question of where these sane Republicans would go if they left their party. The Democratic Party? Lefties should hope not! That is, at least not in such quantity that they could meaningful change the ideological lean of the party.

Although this question does also put more light on the need for a better way of electing lawmakers - preferably some sort of proportional representation, so we can have more parties and not artificially prop up parties the public has long wanted to dispense with.