As Hurricane Katrina smashed through New Orleans, the nation was riveted by images of mothers and children, left destitute by the storm's destruction. Social critics were quick to call attention to another tragedy lying behind the immediate devastation of the storm: the tragedy of persistent poverty in a nation of abundance. Many in New Orleans, they claimed, were victims, not merely of the hurricane, but of social and economic forces that left them trapped in poverty, at the margins of society. New Orleans became a metaphor for the enduring problem of American poverty.

Historically, New Orleans has had a high poverty rate, especially among children. In 2004, some 38 percent of children were living in poverty, more than double the national average. These figures are a cause of national concern. Why are so many children in New Orleans, and the nation at large, poor? Clearly, limited education and joblessness play a role. But a critical factor, ignored by too many commentators, is the collapse of the family. Nationwide, children born and raised outside marriage are seven times more likely to live in poverty than are children in intact married families. Nearly two-thirds of all poor children live in single-parent families.

Most of the New Orleans poor, wading through flood waters to precarious safety, were black. The press often argues that race, not marriage, is the key to explaining persistent poverty. But in America, race, poverty, and marital collapse are inextricably entangled. Black children have higher poverty rates mainly because blacks have lower marriage rates. Black children raised by married couples are almost as unlikely to be poor as whites raised in the same manner (12 percent to 8 percent respectively). The problem is that comparatively few black families are intact.

Sixty-eight percent of black children are born out of wedlock. This problem is compounded by the fact that (among both blacks and whites) out-of-wedlock childbearing is correlated with low levels of maternal education. Overall, the women who are least capable of supporting a family are the most likely to go it alone.

Liberals often argue that blacks do not marry because black men's wages are not sufficient to support a family. History says otherwise: At the beginning of World War II, over 80 percent of black children were born inside marriage. Black men's wages at the time were $639 per year: around $8,000 in today's terms. The figure is now about $30,000, or nearly four times higher than 50 years ago - but only 32 percent of today's black children are born inside marriage. Historically, black out-of-wedlock childbearing skyrocketed while black men's wages were rising, both absolutely and in comparison to whites. Something other than men's wages must explain the collapse: changing cultural norms, for one, and a welfare system that pays women to remain single.

New Orleans provides stark evidence of the results. There, the out-of-wedlock-birth rate is, like the child-poverty rate, roughly twice the national average. And poverty isn't the only problem created by the absence of fathers. Children raised in single-parent homes are much more likely to have emotional and behavioral problems; to fail in school; to abuse drugs; and to become involved in crime.

Marital collapse is also the primary cause of welfare dependence in the nation. Last year, government spent over $200 billion on means-tested aid for low-income families with children. Some three-quarters of this sum went to single-parent families.

Among all races, nationwide, roughly one child in three is now born out of wedlock. Half of the single mothers are cohabiting with fathers at the time of birth. While these men may not be stellar earners, they have, on average, higher earnings capacity than the women do. Detailed survey data show that if poor single mothers were married to the fathers of their children, some 60 percent would be immediately raised out of poverty.

A second major cause of child poverty is a low level of parental work. Even in boom years, poor families work, on average, only 800 hours per year. This translates into 16 hours per week. If the level of work in each poor family were raised to 40 hours of work per week through the year, the child-poverty rate in America would be cut by 70 percent. National welfare reform, which created the Temporary Assistance to Needy Families (TANF) program in 1996, significantly increased levels of parental work. Welfare mothers were required, for the first time, to prepare for employment or perform community service in exchange for benefits. As a result, welfare caseloads plummeted, employment of single mothers rose, and poverty among blacks and single-parent families fell dramatically.

Unfortunately, TANF work requirements have lapsed. Renewal has been stymied in the Senate for several years, leaving welfare reform little more than a hollow shell. The work rules must be reinstated, and similar requirements established in such programs as Food Stamps and public housing. But imposing work on welfare mothers is insufficient to meet the most serious problems of the poor. Making single mothers work may raise incomes somewhat, but it has little effect on the surrounding culture of the underclass: drug abuse, promiscuity, and violence. These pathologies will not be uprooted by mere work requirements. A real war against poverty must be a campaign for moral renewal; its heart must be a long-term effort to rebuild marriage.

Columnist William Raspberry has proposed a reasonable first step for this process. He argues, quite simply, that at-risk young adults must be told the basic truth that "non-marriage has consequences" - most of them harmful. Raspberry asks: "Isn't it worthwhile to spend more time and resources helping young people to understand the economic implications of single parenthood before they become single parents? Wouldn't it make sense to rethink our relatively easy acceptance of out-of-wedlock parenting?"

The sad reality is that the truths about marriage are almost never explained to the poor. Government spends billions each year providing near cradle-to-grave services for single mothers, but nowhere in the process is one likely to find any useful information, or a kind word, about marriage. President Bush has proposed a marriage policy that mirrors Raspberry's ideas. Dubbed the "healthy marriage initiative," the plan is future-oriented, aimed at reducing the next generation of out-of-wedlock births. It would inform young people in at-risk communities of the long-term benefits of marriage and the perils of single parenthood. It would provide low-cost training in relationship skills that are helpful to a marriage. Finally, it would experiment with reducing welfare's penalties against marriage. Since the social and economic costs of single parenthood are huge, and the costs of the proposed pro-marriage activities very low, a marriage-strengthening program can be cost effective with even a modest success rate.

Moreover, the Bush proposal would impose no new costs on the taxpayer; instead, it would divert a minute slice of existing welfare spending ($300 million per year) into pro-marriage activities. If the healthy-marriage initiative were enacted, government would spend only one penny on strengthening marriage for every $5 it spends subsidizing single parents. Nonetheless, liberals remain ambivalent; the president's marriage initiative has languished in the Senate for several years.

There is considerable evidence that many in poor communities would respond positively to this commonsense approach. Teen pregnancy and childbearing have gone down sharply over the past decade, in part because society has sent a very clear and consistent message that teen childbearing is a bad idea. Regrettably, the reduction in teen births has simply meant that girls are waiting until they are a little older before giving birth out of wedlock. Unmarried girls who would have had a baby at 18 now wait till they are 20; little is gained by this. (The typical unmarried mother is now 22 when she gives birth.)

Most unmarried couples who have children are not hostile to marriage. On the other hand, they do not see that marriage should play an important role in the bearing and raising of children. In the middle class, couples first build solid relationships, then marry, and then have children. Among the poor, this sequence is generally reversed: Children are desired and childbearing comes first. Strong relationships and marriage are postponed to some indefinite future. Most unmarried fathers drift off after a few years, leaving the ill-equipped mother and child to struggle on alone.

Sociologist Kathryn Edin has shown that poor women have conventional life goals. They want a house in the suburbs, a husband, kids, and a dog. The difficulty is that they lack a practical plan for achieving these goals. Poor women tend to view marriage as a ceremony, late in life, that celebrates middle-class status. They fail to see marriage as a necessary and demanding pathway leading to social and economic success for themselves and their children. Such faulty ideas lead to bad decisions about boyfriends and babies. The good news is that such confused thinking is fixable, if society makes the effort. Similarly, low-income men are initially attracted by sexual freedom, but often end up disillusioned when freedom leads to a lonely life separated from children and loved ones. Many low-income men were abandoned by their fathers and do not wish to repeat this pattern with their own children; such individuals seem open to change if anyone bothers to help.

Some conservatives may balk at positive government action to strengthen marriage, even on a modest scale. They will claim that the real solution is to eliminate welfare for single mothers: Abolish the rewards of single parenthood and you will end out-of-wedlock childbearing. Even if true, this argument has the drawback that not more than a dozen Republicans in Congress would vote to scale back substantially, let alone eliminate, the large subsidies currently flowing. Ideological chest-thumping about "ending welfare" merely preserves the dysfunctional status quo; meanwhile, marriage withers.

More than 40 years ago, Daniel Patrick Moynihan warned of the tangle of social pathologies that would emerge as marriage eroded. Moynihan was excoriated, and an implicit gag rule developed, muzzling future discussion. Debate about the poor degenerated into a social ritual in which the main cause of poverty was seldom mentioned. The post-Katrina debate follows this pattern. From the right to the left, discussions focus on jobs and construction, joined with occasional proposals about relocating dysfunctional families or voucherizing services. But it is families, not houses, that really need rebuilding. If the proposals continue to ignore the social causes of poverty, they will merely reproduce the original slums of New Orleans in fresh concrete. Twenty years from now, another hurricane will swamp the city and pundits will wonder again where all the poor folks have come from.

The poor deserve more. As the War on Poverty limps into its fifth expensive decade, Republicans should finally face up to the core problem of family disintegration, and experiment boldly. There can be no absolute guarantee of success, but refusal to act will ensure failure.

Robert Rector is a senior research fellow domestic policy studies at the Heritage Foundation.