CHAPEL HILL - We are, to put it mildly, amidst a breathtaking presidential election. The most compelling and inspirational candidate in four decades appears poised to loosen the bounds of history. Yet a recent Associated Press poll claims "racial attitudes" of white voters will dramatically burden his prospects. The financial system seems ready to implode. We're instructed to embrace, once again, a stunning economics -- cutthroat, high-risk, take-no-prisoners, windfall capitalism on the way up; and smooth, silky, safety-net socialism on the way down. All the while, a war continues in Iraq, initiated in violation of international law and American ideals, where over 4,000 of our patriots have lost their lives.

It's no surprise that many experience a political, social, intellectual and partisan overload. Let me apologize for adding to the list.

The U.S. Supreme Court opens a new session tomorrow. So intense are the roilings of our politics that the impact of the Obama-McCain race on the future of American constitutionalism has been little discussed. But that's not because the stakes are modest -- anything but. For those who still struggle in the shrinking valley of uncertainty, I offer a modest primer.

The average age of the nine members of our highest court is 68. Seven are older than that -- most of whom pass for moderates or liberals. John Paul Stevens is 88; Ruth Bader Ginsburg, 75; Anthony Kennedy, 72; Stephen Breyer, 70; David Souter, 69. The next president will, no doubt, have seats to fill. And John McCain has been explicit about how he plans to fill them.

McCain has promised the right flank of his party he will appoint only archconservatives. He'll deliver, he proclaims, judges to match his beau ideals -- Antonin Scalia, Clarence Thomas, John Roberts and Samuel Alito. If he keeps his word, we're in for a path-breaking ride.

As is almost always the case, the current court is deeply divided on many of the crushing civil and political rights disputes of the day. A surprising number of the most controversial and society-changing rulings are 5-4 decisions. The addition of one, or two, or three, new justices to the social conservative camp will work far-reaching change.

The court's modest gay-rights decision in Lawrence v. Texas -- proscribing the most egregious actions to marginalize homosexuals -- would likely be reversed. The wall of separation traditionally assured between church and state -- significantly weakened and pock-marked over the last decade -- would likely be reduced to rubble. I have more experience on this front than I might wish. A public Christian hegemony is not the key to a successful global future.

Other paths are even more clearly defined, or under way.

The addition of Roberts and Alito has already markedly changed abortion jurisprudence. Last year's late-term abortion ruling was, for most, patent writing on the wall. Activists warned that "until this decision, people were skeptical that Roe could be overturned." On his Web site, McCain pledges to do so. One term, one judge, will do the trick.

Affirmative action looks the same. Chief Justice Roberts' opinion in the Seattle school district is bold enough to place the Michigan higher education decision in its sights. So a flat constitutional prohibition of affirmative action seems on its way. Adding to the Scalia-Thomas bloc would make that a certainty.

A bare majority of the current court has stood fast, and with courage, against the Bush administration's lawless efforts to evade constitutional accountability. Restricting the executive's ability to declare citizens strangers to the Constitution or place detention centers beyond the reach of law, justices have declared that "security requires fidelity to freedom's first principles." McCain responded that the Guantanamo case "is one of the worst decisions in the history of the country." His vaunted independence apparently doesn't extend to courts.

Finally, last spring the court plowed radical new ground by invalidating D.C.'s handgun law under the Second Amendment. Speaking in sweeping, categorical terms, the five most conservative members drew thousands of gun regulations into question with an unprecedented interpretation of the right to bear arms. McCain appointees will assure that the Heller case's ample stream becomes an unwelcome river. It's an odd time to conclude that our governments, alone among the great democracies, lack modern powers to restrict firearms.

McCain is, perhaps, moderate on many fronts. Judicial selection isn't one of them. As we cast our franchise, it may be well to remember that a vote for McCain is a vote to end the constitutional right to choose, to dramatically hamper our efforts at integration, to place the presidency above the rule of law and to bolster the American scourge of guns.

(Gene Nichol is professor of law at UNC-Chapel Hill and a former president of the College of William & Mary.)

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