The Decline of Marriage
According to Barbara Dafoe Whitehead's 1997 book The Divorce Culture:
[A]pproximately 45 percent of children born to married parents are likely to experience parental divorce before age eighteen.
This number looks about right given other data I've seen on divorce. Of course, lots of children are not born to married parents. In Denver, the percentage of children born to an unmarried mother, by ethnicity, is as follows:
Native American: 66.7%
The general trends are similar across the nation. The odds that a child born to a black mother in Denver will live eighteen years with both parents are on the order of 18%, while the odds that a child born to a white mother in Denver will live eighteen years with both parents are on the order of 47%.
In fact, however, the deck is stacked. Children of middle class parents are more likely to be born to married parents who are in turn less likely to get divorced. As the Economist (via Non-Prophet) explains:
Only 4% of the children of mothers with college degrees are born out of wedlock. And the divorce rate among college-educated women has plummeted. Of those who first tied the knot between 1975 and 1979, 29% were divorced within ten years. Among those who first married between 1990 and 1994, only 16.5% were.
At the bottom of the education scale, the picture is reversed. Among high-school dropouts, the divorce rate rose from 38% for those who first married in 1975-79 to 46% for those who first married in 1990-94. Among those with a high school diploma but no college, it rose from 35% to 38%. And these figures are only part of the story. Many mothers avoid divorce by never marrying in the first place. The out-of-wedlock birth rate among women who drop out of high school is 15%. Among African-Americans, it is a staggering 67%.
Child bearing patterns are also changing. The well to do are having more children, but having them later. The less affluent are having fewer children.
Many people who have studied the matter have found evidence that having married parents for an entire childhood is better for children than having parents who live apart in all but the worst marriages (e.g. here, here, and some of the statistics from here). The Economist article cited above also noted that low income families that did stay married tended to be better off economically than those that did not. So there is real reason to believe that declining marriage rates and marriage stability are a problem, in general and particularly for the well being of children.
Why? Theories That Don't Work
There are obvious policy culprits. No fault divorce, for example. But no fault divorce doesn't do much to explain why people do not get married in the first place.
This theory also fails to explain why several thousand state lawmakers of all political stripes, in all but a handful of states, under no federal pressure to do so, and in the absence of a strong pre-no fault lobby for it (no fault reduces the amount of work to be done in divorce for lawyers, among other things), backed it so unanimously if it was really so harmful. And, no fault divorce alone fails to explain why college educated couple stay together at such high rates, relevant to less affluent couples.
And the no fault divorce theory fails to note that divorce rates started climbing long before no fault divorce went mainstream.
Secularization has been proposed as a theory too. Those not affiliated with any religious group tend to have higher divorce rates, although, according to Barna, people who identify as atheists have very low divorce rates. Barna also states that evangelicals have high divorce rates, something confirmed by the fact that areas with many evangelicals, like Colorado Springs, are known for their high divorce rates.
Ultimately, secularization fails as a theory because it fails to explain the race and class disparity we see in divorce and lack of marriage. African Americans are the least secular ethnicity in America. Less educated whites tend to be less religious than college educated whites, and equally important, the differences between the two groups religiously isn't huge, but the unmarried parenting rates and divorce rates are dramatically different.
Some people even blame rising taxes for the woes of the typical family. But surely this can't be right, because federal income taxation has virtually vanished for moderate income families with children who tend not to marry and stay married, while remaining meaningful for the higher income couples that tend to get married and stay together. One could argue, I suppose that high income couples need marriage to mitigate tax burdens, while low income couples do not, but it isn't an easy case to make.
Why? An Economic Theory
Economics seems much more plausible as a cause.
One economic theory argues that the key factor that historically kept marriages together was the economic dependence of mothers upon their husbands. The erosion of this dependence, which can be documented in the right time periods, goes a long way towards developing a theory that fits the facts.
Since the 1970s, the incomes of college educated people have surged, while the incomes of men without college educations has remained more or less stagnant. The drug war has turned a lot of men into felons, and while people of all races and classes are drug users (at fairly similar rates across race lines), minorities and the poor are disproportionately the subject of law enforcement attention for doing so.
Meanwhile, women of all economic stations have seen dramatically increased earning power since the 1970s.
I also suspect that gender disparities in income are greater in college educated couples with children, than among those with no college.
Income is closely tied to economically useful skills which are in turn closely tied to education and experience. In less skilled jobs available to those with no college education, particularly for women who tend not to obtain alternative forms of education in a skilled trade, experience is less of a factor in income, so there is a modest long run income earning ability penalty for leaving the work force to raise children. In the highly skilled jobs available to women with college educations, experience tends to be a very important factor in income earning ability, so the long term income earning ability price of leaving the workforce for even a fairly brief period of time to raise children can be very high. Very few men at any income level leave the workforce.
Further, college educated women married to college educated men have greater freedom to sacrifice their income earning potential in order to pursue other objectives, like family, than women married to less affluent men, whose families need their earning capacities more than their time. In less educated couples, the economic pressure for everyone to maximize their income as the cost of living has risen while wages of stagnated is greater. This, in turn, has had the unintended side effect of reducing economic dependence of wives upon husbands.
The timing is right here as well. The cohort of women who married in the early 1970s were living in a period where women's economic prospects were improving dramatically. In contrast, women's economic prospects had stabilized a great deal in the decade after the marriages of the cohort of women who married in the early 1990s, and an increased desire for balance between work and family, particularly for college educated women, had emerged at that point.
One of the other periods in which women's ability to earn income surged, while the income earning ability of many men was disrupted, i.e. World War II, was notably, followed by one of the biggest pre-"no fault" upward bumps in the divorce rate. The baby boom, in contrast, and the associated surge in early marriage, came at a period of greatly increasing economic opportunities for men as the post-war economy took off, while economic opportunities for women had plunged as men returned from war and squeezed women out of the jobs that they had previously held. These two major bumps took place against a backdrop of slowing improving economic opportunities for women all through the 20th century, which coincided with rising divorce rates (although they remained low in absolute terms), apart from these bumps.
Thus, one likely cause of rising unmarried parenting and divorce rates is that women, particularly less educated women, are far less economically dependent upon their spouses than they used to be. This is consistent with the anecdotal evidence that wives are much more likely to initiate a divorce than husbands.
It is also true that a majority of divorced people remarry in less than four years. If your current spouse is a high school dropout, or at least, has no college education, the odds that a new spouse will be better educated and more affluent are fairly good, while the odds that a new spouse will be less well education and less affluent are low. But, if your current spouse has a college degree, the risk of remarrying into a less socio-economically beneficial match are much higher, and the odds of securing a more socio-economically beneficial match are lower.
The high likelihood of a fairly prompt remarriage helps explain why women are willing gamble on enduring an expected great drop in standard of living (on average 45%) until remarriage, in exchange for the prospects of securing improved well being in the long term.
Economics can also explain the disparity in rates of marriage in the first place. College educated couples will typically have substantial marital property to divide upon divorce, health insurance benefits made possible as a result of the marriage, and a husband with an ability to pay maintenance in addition to child support, so the economic risk to women associated with not marrying is high, if the couple is economically unequal, as most educated married couples with children tend to become.
Less affluent couples typically have nothing but their impoverishment and debt (often in the name of the husband) to allocate upon breaking up and often have no health insurance for a non-working spouse to lose (the uninsured are disproportionately young adults and children). Often the husband has a limited capacity to pay maintenance in addition to child support, due to a low and often irregular income, and the increased costs of living associated with maintaining two households rather than one. So, working class women often lose much less by not getting married before having children.
And, economics can explain the extremely low rates of stable marriage for African Americans, because African American women tend to progress significantly further educationally, and to suffer less economic disabilities as a result of criminal records, than African American men. Among ethnicities, men tend to do better economically than women, despite sometimes slightly lower levels of education and much higher rates of incarceration, because incarceration is rare enough to have a small effect, and reasonably high incomes in skilled trades counterbalance income deficits associated with lower educational achievement.
While the economic theory seems to fit the facts, it is not necessarily intuitive.
College educated women, who often have even formally studied feminist theory, and perhaps even taught it, tend to be much more commited intellectually to the notion of marriage as an equal partnership and economic independence for women. It may seem absurd to them that they have less equal economic relationships with their college educated, politically correct husbands than couples where neither went to college and both attend a church that calls for women to submit to their husbands (to which both members of those couples often have an intellectual commitment). After all, most college educated mothers do eventually work and do earn more than less educated women do.
But, most college educated mothers are also married to men who make much more than the husbands (or boyfriends) of less educated mothers. Also, far fewer college educated women are married to men who are economically hopeless.
This economic theory of marriage rates, moreover, argues that personal values about marriage, on average, aren't all that important determinants of marriage and divorce rates. People make these decisions based upon their options and situations, not because they do or do not believe in marriage as a general principle.
Another plausible alternative is that women are willing to stay with men who try to appear non-sexist, which college educated men do to a greater extent than less educated men. But, overt embraces of sexism could also be a response to an undermined economic security. One would also have to explain what motivated increasing sexism or declining tolerance for it.
One way to interpret a fairly dramatic global rise in a belief that marriage should be about love, rather than economics, in the developing and developed world in recent decades, is that people are subconsciously seeking the strongest possible alternative to the marriage binding glue of economic dependence, a glue that is increasingly becoming ineffective.
More generally, if economics is providing a weaker bond to hold marriages together, something needs to replace it. For example, several observers have proposed that no fault divorce be reformed to make divorce harder to obtain for people with minor children, than for people who do not have minor children. Alternately, the economic incidents of marriage could be imposed upon unmarried couples who have children together, in a modern form of common law marriage. Along these lines, economist Robert Stonebreaker has argued that greater economic responsibilities for fathers would reduce unmarried parenting (and incidentally also argues that the evidence does not support welfare policy as an important factor).
Few liberals, moderates or moderate Republicans would consider reducing the economic earning power of less educated women, or reinstating gender based discrimination in pay to be acceptable ways to increase marriage rates or reduce divorce rates.
Of course, another way to create economic dependence in marriage, without harming women's economic prospects, would be to encourage socio-economically diverse marriages. If our society abandoned the prevailing trend towards assortive marriage in which one marries ones socio-economic equal, and embraced marriages between people who are clearly economically unequal, one could have economic dependence in marriages while embracing gender equality in the workplace. College educated women would have to start finding less educated men willing to become homemakers en masse, while college educated men would need to develop a strong distaste for college educated women (something that women often claim they do (at at least used to do), but doesn't seem to be backed up by the recent evidence). It isn't clear that people actually want to enter into these kinds of relationships, however, for a variety of reasons, outside the quite small pool of men who seek "mail order brides."
Policies that support being married can and do secure broader support, but most women who divorce already pay a high economic price for doing so until they remarry, and most people whose marriages end don't stay unmarried for very long. Policies that simply favor being married don't necessarily encourage people to stay married to the same person. Remarriage is clearly economically beneficial for divorced mothers. It is far less clearly beneficial for the children of divorced mothers.
To the extent that weakening marriages are an indirect product of financial pressure on working class families, a partial solution may be to combat the larger issue of growing economic inequality, increased pressure to make ends meet, and economic insecurity for these families. Some of this may need to be through direct government intervention, some of this may be achievable by increasing the earning ability of working class people through improved education and skill training. Most European countries provide far more economic benefits to mothers than the United States which does not even have mandatory paid maternity leave.
Another widely acceptable approach is harm reduction. If unmarried motherhood and divorce are our unavoidable economic destiny, we should, at least, make the process less damaging by finding better processes to mediate split ups and by developing norms and legal rules that make new, more complex families easier to manage. People like Stephanie Coontz have embraced the trend as inevitable and argue that international experience shows that many of the harms to children associated with divorce in the United States are avoidable.
On the other hand, trends to try to restructure the work place to make it more friendly to mothers, which are widely desirable on other grounds, may reduce the economic sacrifice associated with becoming mothers that many college educated women make now. This, in turn, could cause the weakening of marriage seen among less educated and affluent couples migrate up the social ladder to the upper middle class. Sweden, for example, which has very strong government imposed economic protections for mothers in the workplace, also had very high rates of unwed motherhood (more than 50%).
While I am reasonably comfortable that the economic theory described above does explain what we are seeing, and it does give insight into how different proposals might work, I don't think that I know enough about what is causing unmarried parenting and divorce to be harmful to have a pat answer regarding the best response to this trend.