Jonathan put it better: "Well, let's say that single mothers are more vulnerable to economic shocks and are more concerned about the safety net." Much more diplomatic. Single voters were a key demographic in 2012 (if the percentage of married voters had been what it was in 1980, Romney would have won) and there is little reason to imagine that their importance will wane in the future. Singles increased their share of the vote from 2008 by 6 points.
Until about 1970, the percentage of the adult population in America that was married never dipped below about 93 percent. Since then, marriage has been steadily declining. Today, about half the population is single. The unmarried represented about 40 percent of the electorate, and they broke heavily for Obama -- by 16 percentage points among single men and 36 percentage points among single women -- giving him two-thirds of his margin of victory. (By contrast, Romney prevailed among married voters by 56-42.)
The marriage gap is also an education gap in America. Those with little or no college, and particularly those without a high school diploma, are shunning marriage in favor of cohabitation. The college-educated, by contrast, are still marrying at close to the rates they did in the 1950s (though later in life, which contributes to lower fertility). Stable families among the elites perpetuate their status, providing their children with the financial and emotional stability necessary to lead fulfilling lives. Highly unstable families among the less educated lock in inequality, as well, prompting Charles Murray to call upon the elites to "preach what they practice."
It isn't a matter of urgent national importance when non-parents choose to live together without benefit of clergy (love the old fashioned expression). When children come into the picture, it is. There is simply no controversy about the data: Two-parent married families are best for children -- and best for society.
According to the Census Bureau, one of three American children grows up in a home without his biological father. These children are almost four times more likely to be poor (44 percent) as are children from intact families (12 percent).
Fatherlessness (and while there are some single fathers raising children, they are a small minority) is associated with increased incidence of every measurable pathology. It is evident from birth, and even before. Children of single mothers have higher rates of infant mortality, receive less health care, perform more poorly on post-natal tests, are slower to gain weight and have more complications. Babies with a father's name on their birth certificates are four times more likely to live past age 1 than those without.
In school, the pattern holds. Children from single parent families tend (and these are aggregates, not universals) to get lower grades, have more behavior problems, experience higher rates of depression and other mental illnesses and drop out at higher rates. Children of single parents are more likely to be unemployed, get into trouble with the law and be incarcerated. (Source: National Fatherhood Initiative.)
Cohabitating couples are far more likely to separate than are married couples, which means children often live with non-relative adults. A child living with his mother and her boyfriend is at maximum risk. The American Academy of Pediatrics reported that children in such households are 50 times more likely than children of intact families to be the victims of physical or sexual abuse.
There are simply reams of social science data showing that marriage is the best institution for adult and child happiness/flourishing. But it seems that in America today, only activists for same sex marriage are enthusiasts.
The state can prevent single mothers and their children from falling into destitution, but with fewer and fewer Americans marrying and providing stable homes and reliable earners, the pool of resources available to support more fragile families shrinks. The Democratic party cheers these trends for now -- but in short order even they will find they've sawed off the limb to which they are clinging.