This Saturday in Orlando, at a meeting of state party chairs, a parade of potential candidates are going to be making the case for why they should be the next chair of the Democratic National Committee. I don't have a candidate. But I do have a litmus test: Anyone raising the idea that the party needs to "move to the middle" should immediately be escorted out of the building. Better yet, a trap door should open beneath them, sending them plummeting down an endless chute into electoral purgatory – which is exactly where the party will be permanently headquartered if...