Perhaps marriage is a matter of romance, an amalgam of love and chemistry, a choice made for reasons spiritual, soulful and biological.

But perhaps there’s some economics involved.

The loss of manufacturing jobs has made men—especially rural men—less valuable as marital partners leading to a decline in rates of marriage and an increase in the number of children born to unwed parents, according to a paper from the nonpartisan, Cambridge-based National Bureau of Economic Research. 

Between 1970 and 2008, the proportion of American women between 25 and 39 with only a high school education who married dropped by 20 points. Among college-educated women, who were more likely to have good jobs, marriage rates dropped by 10 percentage points.

But it ain’t a sudden lack of romance. It’s the falling “marriage-market value of young men,” the economists argue. The last 30 years have seen a drop in marriage rates a rise in the share of children born to unmarried mothers, they write:

“A potential contributor to both phenomena is the declining labor-market opportunities faced by males, which make them less valuable as marital partners.”

In Georgia, the marriage rate dropped by 36 percent between 1990 and 2012, according to the most recent data from the Centers for Disease Control.

During that same period, the number of manufacturing jobs fell 30 percent, according to the Bureau of Labor Statistics.

The economists shuffle through decades of data and conclude that much of the damage done to the traditional family can be pegged to “trade shocks.”

That is, the kind of shifts that decimate opportunities for young men – the kind of upwardly-mobile jobs in manufacturing that were available to high school graduates a generation or two ago.

The political impact, of course, was evident in November, when Donald Trump overwhelmingly won rural America.

And the change in social behavior is likewise visible, the economists write.

“The falling marriage-market value of young men appears to be a quantitatively important contributor to the rising rate of out-of-wedlock childbearing and single-headed childrearing in the United States,” the report reads.

The change started earlier – during the 1960s and 1970s – in the cities among African-American communities.

Back then, there was a heated and public debate about changes in family patterns, the decline of marriage, the trend toward families headed mostly by women in which there was either a series of men over the years or no man at all.

Critics often called it “a pathology,” a self-imposed, self-destructive and self-accelerating decay of culture. And as time passed, the situation seemed to grow even worse – especially with the introduction of drugs and drug-centric violence.

It took the work of sociologist William Julius Wilson to make the economic connection: the devastation of urban manufacturing had deprived young men of possibility. What reason did a young woman have to tether herself to someone who might never make a decent wage?

Sure being single was a lousy choice, but there might at least be some government support.

Not everybody accepted Wilson's argument, of course. Many have continued to see the situation as one of culture and choice and not economics (although, to be fair, it really can be all three).

And now those trends are no longer limited to just one ethnic group or just to the inner cities.

Markedly, the low-marriage, high out-of-wedlock trend is especially prevalent in rural America, along with higher unemployment and drug overdose rates.

In fact, the NBER report quotes Wilson at the top of the paper. Wilson wrote that joblessness was "much more devastating" than poverty. And then the authors follow that with a snippet from "Hillbilly Elegy," the much-heralded memoir by J.D. Vance.

Vance wrote about his childhood growing up among "hillbilly transplants," people struggling against economic hardship, trying to maintain a culture amidst a social and economic wreckage. Those people, he emphasized, were Appalachian and white.

When he read Wilson’s work, he was riveted and surprised at how well Wilson had described his own upbringing.

“Wilson’s book spoke to me,” Vance wrote.