“The Poverty Cure: Get Married” promises one recent Wall Street Journal headline. Marco Rubio has called marriage “the greatest tool to lift children and families from poverty.” The George W. Bush administration established a (now-defunct) $150-million-a-year effort to shore up people’s marriages, in the hopes of shoring up their finances too.

And yet, as a new report from the left-of-center think tank the Center for American Progress (CAP) documents, millions and millions of married Americans continue to live in poverty. More than half (55 percent) of the nearly 28 million people in low-income families with children are in households headed by a married couple.

“There are a lot of people struggling who are married, and, increasingly, unmarried, couples with children,” says Shawn Fremstad, the author of the report. “Just putting two people together, including in marriage, isn't enough.”

This is not to say that marriage is not correlated with greater economic well-being. Married families are much less likely to be in poverty than families with a single parent. According to the CAP report, 26 percent of people in families with children and married parents fall below 150 percent of the Supplemental Poverty Measure ($38,000 for a family of four), while 60 percent of people in families with children and a single parent do so.

The question is rather one of causality—marriage may not lift people out of poverty, but financial well-being sure does seem to make marriages stronger. As Kristi Williams of the Ohio State University told Annie Lowrey in The New York Times last year, “It isn’t that having a lasting and successful marriage is a cure for living in poverty. Living in poverty is a barrier to having a lasting and successful marriage.”

So if not an absence of a marriage license, what is keeping families in poverty? No surprises here: Though the economy may be growing, very few people are seeing that money show up in their paychecks, and that means people are struggling. According to Elise Gould at the Economic Policy Institute, rising inequality accounts for a far greater percentage of the country’s poverty problem than does the rising rate of single parenthood. If today’s families looked as they did in 1979 (meaning fewer single parents), the poverty rate would be 1.6 percentage points lower, she finds. If the distribution of income today looked as it did in 1979, the poverty rate would be 7.1 percentage points lower.

However, there is one thing about being married that very much does tend to lift families out of poverty: having two incomes. There’s no demographic in America doing better income-wise than dual-earner households, who on average earn more than $100,000 annually. It’s simple math: Most of the time, two incomes combined is going to result in a sum greater than $40,000. In fact, according to Fremstad, “in 2014, 18 percent of families (with kids) with incomes below 150 percent of official poverty had two or more working family members. And only 3.2 percent had two or more full-time, year-round workers.”

And that’s a big part of the reason that, overall, married couples are doing better than single-parent households—just 7 percent of married couples with two incomes are making less than $40,000, according to data from the Census Bureau. By contrast, of married families in which only one person is employed, 31 percent are in that bracket. (Unsurprisingly, married families with no earners tend to be in the poorest category,  but this group is very small by comparison, with fewer than one million people nationwide.)



So why don’t more married couples in poverty send both adults out into the workforce? Of course, the normal reasons for unemployment are likely suspects: a paucity of jobs in the region where a family lives; a lack of valuable skills on the part of the potential employee; health troubles, both mental and physical; and so on. But one factor may have particular salience for this group of low-earning families with kids: the difficulty of finding—and affording—childcare.

If one parent works, the other parent can stay home and take care of the kids. But once both parents are in the workforce, unless there is another relative around to pitch in, parents will have to pony up for daycare, nursery school, or after-school programs. For many families at the bottom of the income distribution, after childcare costs that second income may not be much of a net boost, and can even be a net loss. As a result, getting a second job may not be worth it, even if their incomes together would rise above that $40,000 bar (and thus put them beyond the count of most poverty measures).

According to research by Gould, childcare for a baby would cost a minimum-wage worker in Hawaii (the state with the median minimum wage) three-quarters of his or her earnings for the entire year. And that’s not even counting the additional costs of having a job, in terms of time and transportation. It’s no wonder that many families decide that it is not worth an entire year of minimum-wage labor for a net gain of one quarter of that person’s income.

And the financial costs are only part of why childcare is so out of reach for many low-income families. “Let's say you have a job that typically has an irregular schedule. Then it can be even harder to find childcare,” Gould says. “And that's more likely to happen in the low-wage labor market,” particularly in sectors such as retail, restaurants, and other service work.

There is some public assistance available to help defray childcare costs, including the Child and Dependent Care Tax Credit, which goes primarily to middle- and upper-middle-class parents, and a program called the Child Care and Development Block Grant, or CCDBG, which is targeted at low-income families. But according to the CAP report, with 853,000 families receiving CCDBG each month of 2014, the program just isn’t cutting it. For many families at the bottom of the income distribution. “Because funding for the CCDBG is capped at an inadequate level and has declined in real terms over the past 15 years,” he writes, “only about one in six children whose families meet CCDBG eligibility requirements actually receive assistance.”

In the end, the underlying dynamic is pretty obvious: More income means less poverty (at least as captured by many statistics), and households with more adults are generally able to bring in more income. This isn’t the result of the magic of marriage but the magic of addition. Unfortunately for many families with just one earner—married or not—one salary is rarely enough to support a household these days, unless that person is quite successful. Today’s often-miserable wages, especially when combined with today’s absurd costs of housing and childcare, mean that basic financial security—to say nothing of a few niceties every now and then—is a circumstance that many such families will never know.