It’s probably difficult to grasp the jubilance of the six gay couples who prodded a judge in Polk County, Iowa, to strike down the state’s gay marriage ban last week. “This is kind of the American dream,” one plaintiff in the case told The Des Moines Register. “It’s pure elation — I just cannot believe it.” After the 2004 election, though, such elation is somewhat perplexing. After all, it was the Massachusetts Supreme Court’s 2003 decision to legalize gay marriage that set off a national movement to ban gay marriage via state constitutional amendments. The movement succeeded not only in...