Cornyn is the seventh Republican Senator facing a primary challenge from the right . Republicans must defend 21 of the 22 Senate seats up for re - election in 2018 . But Walsh said that he does n't see a repeat of what occurred in recent years even though a majority of Republican Senators running for re-election are facing primary challenges . Republicans say earlier tea party backed policies have hurt GOP .
Cornyn is the seventh Republican Senator facing a primary challenge from the right . Republicans must defend 21 of the 22 Senate seats up for re - election in 2018 . Republicans say earlier tea party backed policies have hurt GOP .