When Jeb Bush goes down, he’s taking the rest of the GOP field with him (except Donald Trump).That, at least, is what will happen if Mike Murphy, the head of Bush’s super PAC Right to Rise, gets his way. Right to Rise has $75 million in the bank, and Murphy’s not going to let it go to waste, according to Politico: According to another source close to Right to Rise, Murphy has been floating another tactical shift to potential supporters, suggesting that he might spend the bulk of the $75 million to carpet bomb Rubio, Cruz, Carson, Christie—everyone but Trump....