The McCain campaign has famously spent the past week trying to increase doubts as to Mr. Obama’s nature, background, intentions. Their crowds have been irascible. Here is a warning for Republicans: When your crowds go from “I love you” to “I hate the other guy,” you are in trouble, you are on a losing strain. Winning campaigns are built on love. This is the time for “McCain is the answer,” not “The other guy is questionable.”