The political system of the United States manages to contain, under conditions of peace if not civility, a remarkable range of moral, ideological, and religious conflicts. The conflicts are not so severe as those that led to the Civil War, but they are greater than those that divide most European countries—where public opinion occupies a narrower political range, and religion is not an important element. Because of its size and regional differences, and the historical shadow of slavery and the Civil War, the United States is radically divided over issues of war, taxes, welfare, race, religion, abortion, and sex.

These conflicts are not just about the best means to pursue generally accepted ends. They are about ultimate values. Yet they do not threaten the stability and legitimacy of the system. Except for a small lunatic fringe, citizens of the United States are prepared to accept the results of the political and legal process even when those results contravene some of their most fundamental convictions. Americans vilify one another as bigoted religious fanatics or morally depraved atheists, racist reactionaries or crypto-totalitarian socialists, but they know they will not be put up against the wall if their party loses an election. That Americans can share a common political system with people whose views they despise, and try to fight out their disagreements legally through the pursuit of power under that system, shows that the cohesion of American society is stronger than its divisions.

This cohesion is possible only because of a general commitment to the principles of limited government embodied in the Constitution. Individuals and groups can be confident that they will be protected by the rule of law from the arbitrary exercise of governmental power, and that the way they conduct their lives will be largely exempt from collective control based on majority preferences. The precise definition of the limits on governmental power is controversial, but no one doubts that they exist.

Their importance has been brought home to us again by the current administration’s contempt for the rule of law and its attempts to evade the limits on executive power, under the color of a war on terror. The worst of these abuses, like torture and indefinite detention, have been mostly inflicted on foreigners, but surveillance increasingly threatens domestic rights of privacy. I am optimistic enough to believe that our society’s attachment to constitutional limits will prevent the domestic abuses from going very far; but in the treatment of non-Americans, there is reason to expect the worst, precisely because of their weak or nonexistent legal protection.

Still, Americans continue to be embroiled in virulent conflicts, largely between conservatives and progressives. They disagree about what, if anything, the state should do about economic, racial, and sexual inequality; about the separation of church and state; about sexual and reproductive freedom; and about what limits, if any, to put on the freedom of expression. Conservatives are more interested in enforcing moral standards on the community and protecting private property, and …