More than 300 years later, the old jeremiad is still doing a brisk business. From every political quarter we hear the same story - moral failures vex the nation. But the moral diagnosis is wrong and its political consequences are pernicious. The moralizing divides Americans into a righteous "us" and a malevolent "them." Once those lines are drawn, you can forget about social justice, progressive thinking, or - clutch the chest - universal programs. Instead, the overarching policy question becomes "How do we protect ourselves and our children?" Never mind health care or welfare - build more jails.

Contemporary moralizing stands in a long, unhappy American political tradition. When economic and social problems are transformed into declining moral standards, the hunt is on for the immoral people who threaten the public good. There are always plenty of suspects (though the current list is particularly skewed toward single moms and drug abusers). In the tumult of their witch hunts, Americans ignore an alternative moral tradition that aspires, with Abraham Lincoln, "to touch - the better angels of our nature."

The vice squad - which includes the likes of conservative politicians and writers, right-wing preachers and pundits - has constructed a simple story. Most Americans are good, but we are surrounded by rampant immorality. And that tide of misbehavior threatens America in fundamental ways. This lamentation has three effects.

First, the moralizing reassures. Good people are not to blame for social troubles or economic tribulations. The message resonates precisely because most Americans do consider themselves decent, religious and moral.

Second, the moralizing message drafts readers into a political fight. Each preacher would muster us into a somewhat different battle line in the great American culture war. Popular fronts include: illegitimacy, divorce, crime, welfare, educational discipline, affirmative action, teen pregnancy, Satan, moral permissiveness, abortion, drugs.

Third, the message engages an enemy. And with this we arrive at the crux of the matter. The political result is a great division: a virtuous us, a vicious them. "They" threaten us. "They" are ominous, cruel and depraved. (I'm not making these words up.) In the real world of political passions, fine distinctions among the issues get lost in the tumult. The outcry against sin leads, willy-nilly, to the fight against sinners. What we get is the logic of the witch hunt.

The social divisions get especially intense when sins are projected onto racial and ethnic groups. Then the hidden question becomes: Are these strange people going to slip their moral aberrations into our cultural mainstream?

American racial history is a long, unhappy example. White southerners constructed an image of the former slaves as morally unprepared for freedom. The calumny included a standard roster of vices - laziness, dishonesty, thieving, political corruption. But the heart of the matter, endlessly repeated, was the supposed sexual lust of black men. In his popular history, "The Tragic Era," Claude Bowers reported the prejudice as fact: "Rape is the foul daughter of Reconstruction." As Bowers told it, the story ended happily, virtue triumphant. When "the Klan began to ride ... white women felt some sense of security."

Fast forward this stereotypic paradigm to the most active battle line in the contemporary morality crusades, the war on drugs. African Americans constitute 12 percent of the population and an estimated 13 percent of American drug users. They account for 35 percent of arrests for drug possession, 55 percent of all convictions for drug possession, and 74 percent of all prison sentences. The effect of the war on drugs is to clear the city streets of young black men (and tough mandatory sentences will keep them off the streets).

The story of moral depravity is well worn. Americans have survived their own unprecedented wickedness - many times. The moralizing routine was already old when the Synod of 1679 published its list of sins. The real threat is not moral decline. It is what Americans do to their own society in the name of arresting moral decline.