"The concern we'd like to pursue is what's the substance of this," a congressional source told the Los Angeles Times after emerging Tuesday from an administration briefing on Jose Padilla, a.k.a. Abdullah al Muhajir, the alleged dirty bomber. "We're all for sticking bad guys in the hole, but you've got to have evidence."

But these days, the executive branch is making a neat end run around that tired old principle of "evidence for crimes." If it lacks such evidence -- or insists on keeping it secret -- the president can simply call a person an "enemy combatant" and ship him off to the custody of the armed forces, leaving the suspect with no counsel and no constitutional protections.

The United States has always prided itself on being governed by a written rule of law, not the arbitrary dictates of its momentary leaders. But the imperatives of the War on Terror are eroding that principle.

The dirty bomb story smelled bad from the outset. The FBI and CIA are under fire for lack of information-sharing, among other things. The president promised "pre-emptive action" during a speech at West Point on June 1. Worried talk of dirty bombs has filled the air for months. Presto, Attorney General John Ashcroft is live from Moscow announcing Padilla's custody shift from Justice to the Defense Department, and praising the FBI, CIA, and other federal agencies for their "close cooperation."

Still, elements of the press remained skeptical. Articles appeared questioning the suspicious timing. Democrats and civil libertarians frustrated with the highly selective release of information accused the administration of news-cycle management. But the truth turns out to be even worse: The administration's hand was forced because it was scheduled to have to justify itself before the courts.

If the administration had its way, we'd never have heard of Padilla and his alleged plans to construct a dirty bomb. It was only when it was threatened with having to present evidence of such a plan in court that the government squeezed those lemons into lemonade, took credit for thwarting, in Ashcroft's words, a "terrorist plot to attack the United States by exploding a radioactive 'dirty bomb,'" and pushed Padilla into the never-neverland of military custody.

This is where the rule of law comes in. Padilla is a U.S. citizen. The military tribunal system, at Bush's insistence, is for non-citizens. The administration points back to a 1942 U.S. Supreme Court decision under which U.S. citizens who were also German saboteurs were tried by a military court and executed two months after their capture. But the government is not interested in trying Padilla for a crime; it just wants to hold on to him indefinitely. Deputy Secretary of Defense Paul Wolfowitz told CBS's Early Show, "He's an enemy combatant and as in earlier wars, you can hold an enemy combatant until the end of the conflict." His two bosses -- Donald Rumsfeld and George W. Bush -- have made the same point. "Our interest, really, in this case, is not law enforcement," said Rumsfeld. "It is not punishment." Declared Bush, "This Padilla's a bad guy and he is where he needs to be -- detained."

Some congressional leaders support the administration. "If you aid and abet the enemy, whether you are a citizen or not, you’re not entitled to the rights of due process," says New York’s senior Senator Charles Schumer (D). But how do we know he aided and abetted the enemy? It’s due process -- the very thing the administration is denying Padilla -- that would determine this. This rights-denial is justified by our undeclared war on terrorism -- which is a declared war on anyone the government says is a terrorist.

The Padilla case is part of a pattern of government abuse of power. The government has detained hundreds of individuals in the aftermath of 9/11, holding some on violations of federal law, including immigration law, and others as material witnesses. The American Civil Liberties Union and other groups have sued under the Freedom of Information Act to get such basic information as the detainees' names and names of their counsel. A New Jersey state court ruled against the government's policy of secret arrest and detainment. Some of the cases are deeply troubling. Nabil Almarabh, a former Boston cab driver and terrorist suspect, was kept in solitary confinement without access to either a lawyer or a judge for eight months. If the Bush administration gets its way, Padilla could find himself in the same position for much, much longer.