If you were listening reasonably carefully to last Wednesday's Republican presidential candidate debate, you heard Rick Santorum say, "Charles Murray just wrote a book about this."
The question was about Santorum's remarks on contraception, but his answer addressed the broader issue of "the increasing number of children being born out of wedlock in America." That is indeed one of the subjects -- but only one -- of Murray's new book "Coming Apart: The State of White America, 1960 to 2010."
Murray is a distinguished social scientist, a brilliant miner of data and a colleague of mine at the American Enterprise Institute.
He is no stranger to controversy. His 1984 book "Losing Ground" helped inspire welfare reform in the 1990s. His 1994 book "The Bell Curve" (co-authored by Richard Herrnstein) drew spurious charges of racism, which is perhaps one reason why he limited "Coming Apart" to whites.
"Coming Apart" tells us important things about America and, without intending to, sheds interesting light on the race for the Republican presidential nomination.
Murray's argument is that we have seen a significant decline among whites in what he considers America's founding virtues -- industriousness, honesty, marriage and religiosity -- over the last 50 years.
That decline has not been uniform among different segments of the white population, however.
Among the top 20 percent in income and education, Murray finds that rates of marriage and church attendance, after falling marginally in the 1970s, have plateaued out at a high level since then. And these people have been working longer hours than ever.
He labels this group Belmont, after the upscale Boston suburb.
In contrast, among the bottom 30 percent of whites, those indicators started falling in the 1970s and have been plunging ever since, to historical lows by 2008, even before the onset of the recession and the current economic doldrums.
He labels this group Fishtown, after the Philadelphia neighborhood that has been the home of low-income whites since it was first settled in the early 19th century.
In Fishtown, he reports, one-third of men age 30 to 49 are not making a living, one-fifth of women are single mothers raising children, and nearly 40 percent have no involvement in a secular or religious organization.
The result is that the children being raised in such settings have the odds heavily stacked against them. Santorum made this point vividly, and Mitt Romney chimed in his agreement.
These findings turn some conventional political wisdom on its head. They tend to contradict the liberals who blame increasing income disparity on free-market economics. In fact, it is driven in large part by personal behavior and choices.
They also undermine the conservatives who say that a liberation-minded upper class has been undermining traditional values to which more downscale Americans are striving to adhere. Murray's complaint against upscale liberals is not that they are libertines but that they fail to preach what they practice.
What light does this shed on the Republican race? For starters, Mitt Romney is literally from Belmont, where he raised his family in a large house and now has a condominium, and where he helped build a large Mormon temple visible as you drive by on Route 2. He grew up in another Belmont, Bloomfield Hills, Mich.
Rick Santorum, in contrast, describes himself as the grandson of an immigrant coal miner, a product of Fishtown. He often tells of getting his political start winning two House races in the steel mill suburbs of Pittsburgh.
When you look at where these two candidates are drawing their strongest support, you see a similar contrast.
Romney in 2008 and this year has run consistently strongest in the high-income, high-education Belmonts. Santorum has run strongest in areas with more downscale Republican voters.
Both trends are politically problematic. It is not attractive for Republicans (though it can be for Democrats) to advertise a candidate's appeal to affluent voters.
But it's also true that there just aren't so many voters in Fishtown anymore; voter turnout there is way down. Pittsburgh is our one major metro area with more deaths than births. There aren't as many neighborhoods filled with devout Catholics with large families as there were 50 years ago.
Republicans are choosing between a candidate from a Belmont that's doing just fine and one who claims ties with a Fishtown that isn't what it used to be. Not an ideal choice.