Any candidate for president can fall victim to occasional stumbles, lapses, gaffes and clunkers. But Mitt Romney has a shot at raising ineptitude to an art form. The other day, he had to answer a question about how the economy has fared under the current administration. Before he was done, though, Romney managed to give the impression that if he dove off a dock, he'd miss the water. He also undermined his chief assets in the campaign: a supposed mastery of economic issues and a reputation for competence. Over and over, the former Massachusetts governor has accused President Barack Obama...