We face two opposite prospects. The first is that Americans will finally grasp that what connects the catastrophes in New Orleans and Iraq is a witches' brew of self-delusion, deliberate deception, cronyism, and staggering incompetence on the part of the Bush administration. Republicans, meanwhile, will desert a president who is becoming a plain embarrassment even to his staunchest backers.

But there is a darker possibility, already emerging. The Karl Rove team is gradually getting Republicans back “on message.” To wit: There's no point in playing a “blame game,” as Scott McClellan said fifteen times at Thursday's press briefing. The New Orleans disaster just proves the unreliability of government in general rather than this feckless president in particular. We should be looking forward to rebuilding -- with the private sector taking the lead.

If we aren't alert, Bush will not only wriggle out of the political responsibility for diverting funds from New Orleans' flood defenses, eviscerating FEMA and then bungling the response, just as he evaded responsibility after Richard Clarke's devastating testimony that the administration ignored plenty of warnings about al-Qaeda's plans for a September 11–style attack. Katrina could even be a political windfall, promoting the ongoing campaign to disparage and cripple government, permanently displacing some reliable Democratic voters from the swing-state of Louisiana, causing the political faithful to rally round their beleaguered president, and knocking even more unpleasant news off the front pages and network news.

Here is one such story that has gotten far too little attention. Its outcome should prove an important telltale in the still churning political winds:

Senator John McCain, a conservative Republican and a war hero, has been appalled that the Bush administration's official policy is that prisoners of war in American custody may be deliberately subjected to cruel, degrading, and inhumane treatment as part of interrogations. We are literally the only nation in the world with such a stated policy.

This doctrine, by the way, was devised in 2002 for Defense Secretary Donald Rumsfeld by then White House Counsel Alberto Gonzales, the same Gonzales who the hard right is attacking as too “moderate” to be appointed to the Supreme Court. (Who would be tough enough, Saddam Hussein?)

Senate Armed Services Committee hearings in June made it painfully clear that the administration and its military chain of command still had no coherent directives on just what interrogation techniques were actually permissible -- leaving a few ordinary soldiers like the pathetic Private Lynndie England to take the fall while higher-ups escaped accountability.

So McCain and two other leading Republicans on the Armed Services Committee, Senators John Warner and Lindsey Graham, drafted an amendment making two simple changes. First, U.S. policy was defined as the interrogation procedures authorized by the U.S. Army Field Manual, which specifically prohibits cruel, degrading, or inhumane treatment. Second, all detainees held by the United States, in whatever invented category, must be registered with the International Committee of the Red Cross.

This is not about who “they” are, McCain has said repeatedly. It's about who we are. “We are Americans,” he told the Senate, “and we hold ourselves to humane standards of treatment of people no matter how terrible they may be. To do otherwise undermines our security but it also undermines our greatness as a nation.”

And what did President Bush do? He threatened to veto the entire Defense Appropriations bill if the McCain Amendment were included, and dispatched Rumsfeld and Dick Cheney to twist Republican arms.

Since then, dozens of retired generals, admirals, and other ranking officials have signed letters supporting the McCain Amendment. Brigadier General James Cullen (Ret.), former Chief Judge of the U.S. Army Court of Appeals, told a conference on national security policy in Washington last Monday that the legal experts of the military's own criminal system had been systematically excluded from the setting of interrogation and detention policy after 9-11.

Speaking at the same Terrorism, Security, and America's Purpose conference, the decidedly un-radical Anne-Marie Slaughter, dean of the Woodrow Wilson School at Princeton and former president of the American Society of International Law, declared that “these policies make a mockery of our claim to stand for the rule of law.” Americans, she added, should be marching on Washington to reject inhumane techniques carried out in our name.

After Katrina, will Bush's critics be emboldened, or silenced? Keep your eyes on the back pages.

Robert Kuttner is co-editor of The American Prospect. A version of this column appeared in the Boston Globe.