What we have is democrats registering as republicans to vote in our primary since we so seldom have a contested senate race.
Your state should institute a once a year registration limit.
That would put an end to the crossover in the primaries.
Your RP should drive that home. Get the guy you’ve been mentioning to drive that through.
If you can’t control your primaries, then you’re state is beyond help right now.
One possible alternative would be to place a Conservative on the Democrat ballot. When the Dems switch registrations, elect him to their ticket. That’ll put a speed bump on their highway.