As bush showed you can elect as many footsoldiers you want. they simply vote with the leader of the party. Yuo elect a RINO and you get a RINO congress. you elect a liberal you get a liberal congress and if you elect a conservative you get a conservative Congress.
The POTUs is the spot we need to worry about not the footsoldiers....
In 1980, a conservative, Reagan, was elected president, but Democrats retained control of both houses of Congress.