When Charles James Napier, the British governor of an Indian province in the nineteenth century, banned the ancient practice of widow burning, several local religious authorities objected. “The priests,” his brother William Napier later recounted, “said it was a religious right that must not be meddled with—that all nations had customs which must be respected, and this was a very sacred one.” “Be it so,” the governor replied. “This burning of widows is your custom; prepare the funeral pile. But my nation also has a custom. When men burn women alive, we hang them and confiscate all their property . . . Let us all act according to national customs!”

If custom is all we have, then moral disputes must simply end with an appeal to power, for there could be no intelligible measure or standard of rightful custom. In such a case, moral truth, as Oliver Wendell Holmes used to say, would be decided by a “majority vote of that nation that could lick all the others.” Or, more accurately, the idea of moral truth would be nonsense. Although the British governor may have had something like Holmes’s skeptical aphorism in mind when he appealed to national custom, I rather doubt it. At the bottom of his willingness to use force to prevent the ancient Hindu practice of suttee was more likely a conviction that burning women alive really is wrong; and wrong not only because it offended British sensibilities but because it was unjust according to a standard of right that overarches British and Indian customs alike.

Our own Declaration of Independence from British rule makes just such a claim. “We hold these truths to be self-evident,” the Continental Congress declared in 1776, “that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty, and the pursuit of Happiness.”

And this claim brings us to Jeffrey Bell’s argument in The Case for Polarized Politics: Why America Needs Social Conservatism. According to Bell, an early supply-side economist and current director of policy at the American Principles Project, the ideas expressed in the Declaration of Independence provide the unifying core of American social conservatism today; a movement, Bell argues, that “has a chance to alter the trajectory of history.”

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“What divides social conservatives from social liberals,” Bell claims, “is this: Most—not all—social conservatives believe the words in that sentence [from the Declaration] are literally true. Most—not all—opponents of social conservatism do not believe those words are literally true.” In Bell’s account, the key words in question are “truths,” “self-evident,” “Creator,” and “unalienable.” Whether or not you take these concepts seriously, Bell suggests, is a likely indicator of where you fall on the polarizing social issues of our day. “Most social conservatives,” he maintains, “believe, with the Declaration, that our rights would not exist if not for the theistic God who gave them.” “Most social liberals,” however, “believe that equality and human rights are the product of human enlightenment—of progressive self-illumination.” These two different visions, Bell argues, in turn stem from antagonistic conceptions of democracy and human rights that can be traced back to the American and French Revolutions.

In Bell’s narrative, modern political polarization is thus a tale of two enlightenments. The left enlightenment, shaped by the political thought of Jean-Jacques Rousseau and put into motion during the French Revolution, is secular in outlook and aims at “elite management toward equality.” “From its beginning,” Bell notes, “the left attempted to raise up, train, and empower revolutionary vanguards and elites to guide society to its ultimate destination, often at the expense of benighted social groups and individuals tied to the old order.” The conservative enlightenment, on the other hand, largely took hold in the United States, where the country’s founders swore “allegiance to the notion of a universe that rests on self-evident truths, which most of them saw as flowing from a God-centered universe—from ‘Nature and Nature’s God.’”

According to Bell, American social conservatism is the “the clearest ideological heir of the conservative enlightenment.” Social conservatism’s stubborn belief in the quaint ideas of the Declaration does not make it primarily religious or sectarian, however. Instead, Bell says, it “is more accurately seen as the application of natural law to politics—the self-evident truths of the Declaration—rather than as a political manifestation of religious revelation.” Nor has social conservatism been without electoral implications. From 1932 until 1964, when social issues as we know them were nonexistent, the Democratic Party won 7 of 9 presidential elections. Since 1968, an increasingly conservative Republican Party has taken the White House in 7 of 11 contests. Republican electoral success during this time, Bell notes, has often coincided with the increased salience of social issues, ranging from abortion and marriage to welfare reform and religious liberty. When Bill Clinton and Barack Obama did manage to run successful presidential campaigns, it is telling, Bell thinks, that they intentionally downplayed or distanced themselves from social liberalism.

Nonetheless, socially conservative politicians and pundits often suggest that the conservative movement would be wise to shelve the social issues. In a common refrain along these lines, Indiana Governor Mitch Daniels suggested in 2010 that conservatives should simply “call a truce on so-called social issues” and focus on the economy. Mississippi Governor Haley Barbour soon followed suit, claiming that social issues “ain’t gonna change anybody’s vote this year because people are concerned about jobs, the economy, growth, and taxes.” No less a conservative firebrand than Glenn Beck even joined the chorus, suggesting that conservatives “have bigger fish to fry” than limiting abortion or restoring a healthy marriage culture because the “country is burning down” under President Obama’s progressive economic policies. And, of course, the conventional wisdom this campaign season is that former Pennsylvania Senator Rick Santorum is simply too socially conservative to be electable.

By Bell’s accounting, this equation doesn’t add up. Social conservatives, he says, currently have the upper hand in 35 states that collectively hold 348 electoral votes—78 more than are required to take the White House. Bell also notes that the 31 states Bush won in 2004 (when same-sex marriage was a major election issue) were all socially conservative. But even if it were politically prudent to call a truce on social issues, recent developments have taken this option off the table. By targeting traditional institutions such as organized religion and the family, Bell notes, the left has long been the instigator and aggressor in the culture wars. From the HHS mandate to the DOJ’s argument against religious liberty in Hosanna-Tabor v. EEOC to the Ninth Circuit Court’s ruling against traditional marriage, social liberals continue to pick fights that conservatives did not ask for. To call a truce, in this politically charged environment, would be to surrender.

Besides, conservatives could not ignore social issues and fix the economy even if they wanted to, since social pathologies are tied to many of our economic woes. Charles Murray’s recent book Coming Apart, for example, underscores the serious crisis that family breakdown poses for America’s lower classes. Fatherlessness, divorce, cohabitation, plummeting fertility rates, and declining religiosity cannot be separated from entitlement spending, poverty, incarceration rates, unemployment, and education. These issues are bound up together, and they have to be treated as a whole.

All of this brings into clearer focus the book’s subtitle: Why America Needs Social Conservatism. An America without social conservatives, Bell suggests, would simply be Europe—large “entitlements,” “centralized economic regulation, and a virtually dissent-free devotion to the social values of the left enlightenment.” And Europe, as we are beginning to see, is unsustainable. Declining birthrates and a graying population mixed with massive entitlement programs, centralized administration, and a desolate civil society have created a “mix of social and economic policies” that are “capable of bringing on a worldwide demographic collapse.” While nothing in Bell’s account is original, The Case for Polarized Politics is a timely call for “social conservatism and economic conservatism” to “end the fiction that they are operating in separate, fundamentally unrelated realms of human affairs.” The trajectory of world history, Bell insists without hyperbole, depends on it.