The Italian indictment of 13 Americans for kidnapping an Islamic militant from a Milan street and bundling him off to Egypt for harsh interrogation and imprisonment is the first legal test that many in the Central Intelligence Agency have been dreading of American counterterrorist kidnappings and renditions. It may trigger a cascade of legal actions abroad against American officials operating in the shadows of illegality, and even impel U.S. courts to require compliance by recalcitrant executive branch officials.

The Bush administration has not contested the Italians’ account of the facts. Informed by Italian authorities of their meticulous counterterrorism investigation against militant cleric Hassan Mustafa Osama Nasr, C.I.A. officers and operatives kidnapped Nasr on February 17, 2003, flew him in an Air Force jet the next day to a U.S. air base in Germany and thence to Egypt, where he was apparently subjected to torture.

Apologists for the administration’s expansive interpretation of presidential power to combat jihadists, even on other countries’ territory, have been quick to dismiss the Italian court’s indictments as inconsequential: The United States government will never, they aver, allow its intelligence operatives to face legal questioning, much less a trial.

But they may well exaggerate the deference that America’s federal courts will accord to U.S. security services when an allied state charges American nationals with abduction. Blanket claims of executive power to deal with alleged terrorists free of scrutiny have not deterred federal courts from stepping in to assure due process, as in the cases of Guantánamo detainees and José Padilla. They are likely to be equally scrupulous in upholding U.S. extradition obligations to a major democratic government.

Moreover, other European countries’ willingness to work with Americans on counterterrorism will be shaken if Washington stonewalls a criminal proceeding and countenances what seem to be brazenly illegal actions by its agents. By scorning even so loyal an ally as Italy, whose government has taken great political risks domestically to follow President Bush’s lead on Iraq, the administration will erode the lingering incentive for the rest of the European Union to collaborate with American agents.

Judge Chiara Nobili’s arrest warrant for the 13 C.I.A. operatives comes at a moment when European doubts about the Bush administration’s counterterrorism policies are already multiplying. The Pew Research Center’s newest transnational survey has found support for the U.S.-led war on terror crumbling in all seven Western countries polled. Backing for the U.S. campaign has plummeted over the past three years from an average of 71 percent support in 2002 to 48 percent support today—a nosedive of 23 percentage points.

Cavalier U.S. disregard for the law in Italy can only intensify European estrangement. As one senior Italian official witheringly told the New York Times, “Our belief is that terrorist suspects should be investigated through legal channels and brought to a court of law - not kidnapped and spirited away to be tortured in some secret prison.”

Nor can European intelligence services much trust their American counterparts, given the revelation of American officials’ readiness to feed disinformation to their allies: When the Italian investigators building the legal case against the Milan imam asked their C.I.A. collaborators (now indicted as the perpetrators) what they had learned of his disappearance, they replied he had surfaced in the Balkans.

In U.S. law, this would qualify as obstruction of justice. Indeed, the Italian press is recalling the prosecutions that sent security operatives of the Watergate era to prison on just that charge. Career officials within the C.I.A. itself have been warning of the legal consequences that could flow from the no-holds-barred approaches demanded by the administration’s political decision-makers. They understand that the growing internationalization of legal practice and the rule of law means that the intelligence establishment can no longer assume impunity from prosecution, either at home or abroad.

Conservatives and old-school C.I.A. operatives may wax nostalgic for the derring-do practices of secret agents in the first two-thirds of the last century. But the rule of law has caught up with them. Crimes of state are no longer exempt from justice. The war crimes tribunals in Yugoslavia and Rwanda, and the 1998 Spanish demand for extradition of Augusto Pinochet, have firmly established an obligation (and multiple avenues) to ensure respect for law internationally. And Americans have ringing domestic precedents as well.

Senior officials in both the Nixon and Reagan administrations had believed that national security could trump any squeamishness about illegality by the security establishment; the second terms of both were crippled by rippling indictments and convictions. Perhaps the arrest order in Milan may prove the first of a wave of prosecutions to rein in the abuses of the current age.

Jeffrey Laurenti is a senior fellow at The Century Foundation.