As the designated political heir of a deeply unpopular president — according to Gallup, President Bush has the highest disapproval rating recorded in 70 years of polling — John McCain should have little hope of winning in November. In fact, however, current polls show him roughly tied with either Democrat. In part this may reflect the Democrats’ problems. For the most part, however, it probably reflects the perception, eagerly propagated by Mr. McCain’s many admirers in the news media, that he’s very different from Mr. Bush — a responsible guy, a straight talker. But is this perception at all true?...