Another GOP departure: CNN has learned @RickSantorum will exit race tonight. Plans endorsement.
Guessing @mikepence has figured out these last 20 mins what being no. 2 to @realDonaldTrump means.
So @realDonaldTrump mocks his running mate. Says @mike_pence caved to pressure to back @tedcruz
whether it's @megynkelly or rivals, @realDonaldTrump gets ticked when his own words are used against him. #GOPDebate