They should talk to Ken Paxton, who is also working to get rid of open primaries. I think TX is having to do it through the party itself making the rules, since Dade Phelan (who won the primary because of democrats voting for him in the open primary) has kept the TX legislature itself hostage to the corruption.
How can any, but the most blatant corrupt, look in the mirror knowing that they were saved by the other side.
Then again, the Phelan situation is all on the voters