 What's the lesson here? In 1980, 1992, both those cases, the incumbent lost, did not get a second term. So I think throughout history, we presume that the president's going to be in charge of his own party and have the support of his own party. But when those cases where someone has made a viable challenge, even if they don't get the nomination, they've weakened and shown chinks in the armor, if you will, of the incumbent.