Scott Walker has dropped out of the presidential race, holding a news conference early this evening. This despite the fact that he began as arguably the best-positioned candidate to win the nomination.

A lot of people will blame Donald Trump. In one sense, they’re wrong, and in another they’re right. Trump, whose backers are mostly paleoconservatives and members of fringe groups coming to Republican politics from the outside, did not gobble up Walker’s base. But what Trump did was to lure Walker into a bidding war he could not win.