If you reward rightward shifts with your vote just as well as you reward leftward shifts. Why would they ever move left, instead of banking your vote and trying to secure more and more rightist votes by moving right? How do you beat fascism by marching along a fascist line?

That fight looks like placing your line in the sand, and once it is crossed those on the other side are your enemies, lest you end up following and drawing new meaningless lines.

That fight looks like working within your communities to spread education and recognition about who those enemies are, and building structure in your community so that when the enemy is identified you can work together to ensure the enemy feels your resistance.

After which, they may just cross that line back over, recognizing that you now see them as an enemy and not an ally, and that they need you if they wish to have success.

If they don't, then that just further reveals their intention was always to march rightward regardless, the only difference is you are no longer marching alongside them and have instead set the groundwork for opposing fascist enemies.