"The slow decline of marriage is upending American politics. In the 2012 presidential election, unmarried women accounted for nearly a quarter of all votes cast. Their votes went decisively to Barack Obama, by 36 percentage points. You might not think that a group that runs from not-yet-married college students to inner-city single mothers and divorced professionals had much in common. Yet unmarried women are spectacularly loyal to the Democrats—if they vote, which many do not. (Widows are outliers, voting more like married women.) The “marriage gap” dwarfs the sex gap, by which women as a whole have long favoured Democrats: Mr Obama beat Mitt Romney by a less dramatic 11 points among female voters."