Aaron Blake: “Republicans choosing to distance themselves from Donald Trump ahead of the midterm elections was somewhat inevitable, given how historically unpopular the president is.”“But the examples are piling up, and it’s notably happening in some pretty red territory.”“Many of those running away from the president and policies like the Iran war are campaigning in territory that favored Trump by substantial margins — including by double digits in some areas.”“The Iran war defections over the past week have been particularly notable.”