Charles Murray's bombshell book on the state of white America paints a dispiriting picture of a huge subsection of U.S. society that seems lost and confused.
In Coming Apart, Mr. Murray points to a decline in religiosity among American whites, especially among working-class whites, as one reason for this unravelling.
Yet, if it is true white Americans are less religious than ever, you wouldn't know it from the Republican presidential race. White evangelical Christians are providing Rick Santorum with the staying power to turn the contest into a fight for the soul of the party.
Indeed, as American society becomes less religious, it seems religion is playing a bigger and bigger role in Republican politics.
"It is not a new phenomenon, but it's particularly evident in this year's primaries," noted John Green, a political science professor at Akron University. "One of the things that make evangelicals so important politically is that, as the whole country has secularized, here is one important religious tradition that has not, or not nearly as much."
One result is that evangelicals are flexing their political muscle in ways they did not, or could not, in previous GOP contests.
While George W. Bush courted evangelicals to capture the nomination in 2000, he was also the pick of the party establishment and its backers in the business community. Mr. Santorum poses a challenge to Mitt Romney on the strength of his evangelical appeal alone.
To be sure, Mr. Santorum also owes his astonishing competitiveness to a few technical factors, not the least of which is the emergence of a pro-Santorum Super PAC, which has allowed a single wealthy benefactor to bankroll a parallel campaign on his behalf.
What's more, new rules that allocate delegates proportionally have made it impossible for the establishment favourite, Mr. Romney, to lock up the nomination as quickly as John McCain did in 2008, when most states awarded delegates on a winner-take-all basis.
That has given later primary states such as Mississippi and Alabama, where Mr. Santorum won this week and where evangelicals accounted for eight in 10 Republican voters, a bigger voice in choosing the nominee.
Without explicitly referencing Mr. Murray's book, Mr. Santorum seems to be giving voice to all of the statistics on white working-class America it contains. And evangelicals across the United States are responding in kind.
Mr. Santorum has crafted a compelling message that draws a connection between American prosperity and the very virtues Mr. Murray suggests have waned among lower- and middle-income whites in America: religiosity, industriousness, honesty and marriage.
It is far from clear that Mr. Santorum can broaden his appeal beyond evangelicals with his call for a kind of religious revival that might help eradicate the social ills Mr. Murray writes about.
Indeed, a 2010 Pew Research Center poll found that white and black evangelicals were the only groups of voters who felt strongly that American political leaders spoke too little of religion in public life. Even among Catholics, only a minority felt that way.
Mr. Santorum's call for more Christian religion in the "public square" has set off a fierce debate over the separation of church and state. Two centuries after Thomas Jefferson first articulated the concept, Americans are as divided as ever about what it means.
What is clear is that Mr. Santorum is no heretic. The First Amendment, which prohibits the establishment of a state religion, was not meant to stop politicians from making public expressions of faith or to banish religion from the public square.
Indeed, if it was, it failed miserably.
"Religion in America takes no direct part in the government of society, but it must be regarded as the first of their political institutions," Alexis de Tocqueville observed in 1840. "The Americans combine the notions of Christianity and liberty so intimately in their minds that it is impossible to make them conceive of the one without the other."
The doctrine of separation of church and state, outlined by Jefferson in 1802, is regularly invoked by those seeking to ban religious symbols or expressions from public spaces.
But as Supreme Court Justice Anthony Kennedy wrote in the court's 2010 decision preventing the removal of a memorial cross in the Mojave National Preserve: "The goal of avoiding governmental endorsement [of religion]does not require eradication of all religious symbols in the public realm."
Rather, the separation of church and state seeks to ensure the free exercise of all religions by preventing the state from favouring any one religion among them. And if that is its true meaning, then Mr. Santorum is among its most public beneficiaries.
Mr. Santorum may still disagree with John F. Kennedy's 1960 discourse on the separation doctrine – even if it no longer wants to make him "throw up"– but he probably could not have reached this point had JFK, a fellow Catholic, not blazed the trail for him.
Mr. Santorum would have had no hope of becoming a challenger for the GOP nomination in Mr. Kennedy's time, much less one thrust into contention by evangelical Protestants.