IF THE GOVERNMENT'S new spree of allegations this week against Jose Padilla had taken the form of a criminal indictment, it would have been a powerful document. The public had previously known only the barest sketch of the case against Mr. Padilla, the American citizen arrested in Chicago two years ago and locked up since by the military as an "enemy combatant": The former gang member turned Islamic radical was alleged to have come back to this country after hobnobbing with al Qaeda operatives, intent on detonating a dirty bomb or committing some other terrorist attack. The new allegations add much detail and portray Mr. Padilla as an extremely dangerous man. If they were proven in court, they would show Mr. Padilla guilty of any number of serious crimes.

Unfortunately, however, the new allegations were not contained in an indictment or in any court document subject to challenge by defense lawyers. They were released in a summary issued by the Justice Department at a news conference held by Deputy Attorney General James B. Comey Jr. Even now that Mr. Padilla has limited and belated access to his lawyer, he has no ability to respond. Not only does he lack a judicial forum in which to do so, his lawyer is tongue-tied: Everything Mr. Padilla has told her in their two conversations, she told us, is classified, so she could not say even if he disputed the new allegations. In other words, on the eve of the Supreme Court's decision in Mr. Padilla's case, which is expected by month's end, the government has delivered a broadside smear against which no defense is possible.

Mr. Comey said at his news conference that his purpose in releasing the material was not to affect the Supreme Court case. Instead, he said, he was troubled by how little the public knew about why the government acted as it did and wanted to release as much information as possible as quickly as it could be declassified. And the allegations are sobering, portraying Mr. Padilla's involvement with top-level al Qaeda figures, training and early-stage plans. But America's justice system is intended to prevent the government from punishing someone without the opportunity to respond to and rebut accusations.

Unlike many civil libertarians, we have never argued that the president should be utterly without power to hold an American as an enemy combatant. There is historical precedent for such actions, and as Sept. 11 recedes it is important to remember that the United States faces adversaries determined to do it massive harm. But even in the extraordinary circumstances in which such a detention is justified, there must be some procedure to determine whether mistakes have been made. The notion that the president can designate any citizen as an enemy and then hold him, without proving any wrongdoing, for as long as the government wants is simply not acceptable.

From the beginning of Mr. Padilla's case, when Attorney General John D. Ashcroft demagogically announced his arrest from Moscow, the government has shown contempt for such concerns. Now Mr. Comey publicly boasts of intelligence gained by holding Mr. Padilla without access to family or lawyer and laments the damage that would have been done had Mr. Padilla been given his rights and elected to remain silent. Trust us, the government is once again saying. But that's not how our system is supposed to work.