During the Democratic debate on Wednesday, one of the moderators asked Barack Obama whether he thought that the Rev Jeremiah Wright, his controversial former pastor, loved America as much as he did. A flummoxed Mr Obama mumbled something about Mr Wright’s spell in the Marines.

Until recently Mr Obama was criticised chiefly for being a man of words rather than experience. Since becoming the favourite, however, the charges against him have become steadily graver. In the past six weeks Mr Obama has faced allegations or insinuations of being a snob, unpatriotic, a neo-Marxist, a closet anti-Semite, a consorter with home-grown terrorists and a devotee of black liberation theology.