Heard the one about the Mormon President? The shaky prospects of Mitt RomneyGerard Baker There are so many minorities now in the crowded field for the 2008 US presidential election that daily news coverage of the race is starting to sound like one of those politically incorrect jokes from the 1970s. You’ll recall the kind: A woman, a black man, an Italian and a Mormon are in a plane over the ocean . . . We have Hillary Clinton, credibly promising to be the first female to be President, Barack Obama, the first African-American in the White House, Rudolph Giuliani,...