system
Given the following post, respond as if you're commenting on Reddit:
human
CMV: The best thing that someone can do to fight Trumpism is register to vote as a Republican and vote in the primaries.

I think there is an awful divide in the country right now, and most people can agree on it.  The Republican party is heading in a very bad direction.  Trump is a cancerous growth that has gone out of control, and the GOP falls in line with him because he has some similar policy goals and they thought they could harness the populism.  But they failed and now are holding onto it for dear life.

Big donors have continued to pull the Republican party to the right during primaries, where the most radical rightwing voters show up to vote in much greater numbers than moderates.  Gerrymandering then allows these crazy people to get elected because the choice is so now so tribal that many people fear an evil Democrat in office more than a legitimately crazy Republican.

The only way for an average citizen to fix this is register as a Republican in any district that has any possibility of a Republican win, and to vote for the most anti-trump candidate.

This is whether you are a Republican or a Democrat, so long as you oppose Trump your primary vote will count for much more when it comes to shaping the political landscape if you can de-radicalize the Republican party.  It doesn't matter if you agree with their other views or not tbh.  Your real vote will be in the actual election.  

Tldr: The best thing you can do as an American voter is to register for the majority party and vote in their primary for the least bad candidate.  This has become vastly more important during the current political era.  CMV

Edit: I would like to clarify, since most of the comments are missing my point.  If you want to change my view, I need an alternative option for what action an individual can take, at this point in the nations history, which will have a larger impact than voting in Republican primaries to bring the party back toward the center.
gpt
It really depends on where you live.

A moderate Democrat may have a better chance of beating a radical Republican in the general election than the moderate Republican has of beating the radical Republican in the primary.

If that is the case and the moderate Democrat is in a primary fight with a radical Democrat (someone who will assuredly lose to the Radical Republican), you should vote for the moderate Democrat in the primary.

Did all of that make sense?