If they can't pass HR1/S1, they are dead meat in '22. Even if they pass it they are 50/50 to lose Congress. There's gonna be more poll watchers and lawsuits than Steinmeyer has beans.
Wouldn't it end up in the Supreme Court, since it involves a Constitutional question? If it does, I would assume that it wouldn't be decided, one way or the other, before the mid-terms.