Evenness of temper has never been one of John McCain’s signature virtues, but yesterday the Arizona Senator had a good excuse for loosing his cool. Henpecked by California’s Barbara Boxer about the poor polling of the Iraq war, of which he has been a resolute supporter, a visibly vexed McCain fired back that “a lot of us are not driven by polls. A lot of us are driven by principle. And a lot of us do what we think is right no matter what the polls say.” Even apart from the deteriorating fortunes of his presidential campaign, McCain was right...