Some 50 delegates were reportedly poised to unite behind Barack Obama if he had won by even 1 point in Texas. He lost the popular vote by 100,000 ballots, and now we learn that 100,000 Republicans voted for Hillary Clinton, probably not because of some change in party allegiance but because they thought she would be the easier candidate to beat. This kind of strategic voting often backfires (think Ralph Nader). The Texas crossovers are winners. By helping to prolong the Democratic race, they can claim credit for weakening the eventual nominee, whoever it turns out to be. Obama has...