I think this week marked a certain coming to terms with where the election is going. Politics is about trends and tendencies. The trends for Donald Trump are not good, and he tends not to change.

All the damage done to him this week was self-inflicted. The arrows he’s taken are arrows he shot. We have in seven days witnessed his undignified and ungrateful reaction to a Gold Star family; the odd moment with the crying baby; the one-on-one interviews, which are starting to look like something he does in the grip of a compulsion,...