IN his opening speech at Nuremberg in November 1945 Justice Robert H Jackson, appointed by President Franklin D Roosevelt, set the standard for the prosecution of war crimes and criminals under international law (Illustration from David Irving: Nuremberg, the Last Battle (Focal Point, 1997). Free download

PHILADELPHIA - President Bush's executive order authorizing military commissions to try foreign nationals suspected of terrorism is a shocking imposition of martial law that goes well beyond any measure previously upheld by US courts.

Though championed on security grounds, it really relies for its dubious legal foundation on one of the ugliest themes in American jurisprudence: the denial that aliens are persons with rights.

The administration's plan is clearly intended to provide a mechanism by which Osama bin Laden could be quickly tried and executed by US military officials overseas, instead of turning him over to an international judicial tribunal for a prolonged public trial that might make him a martyr.

Whatever the wisdom of that grim policy, the order goes much further. It allows military officials within the United States

• to arrest aliens on mere suspicion of terrorism, without having to show probable cause;
• to try them entirely in secret;
• to use any evidence against them that military officials judge to have "probative value," even if it is mere hearsay or illegally obtained;
• to convict them on simple preponderance of such evidence, rather than proof beyond a reasonable doubt;
• to convict them by a vote of two-thirds of the military judges, without a requirement of unanimity, much less trial by jury;
• and to sentence them to death, without appeal to the civilian courts.

This is a grotesque Magna Charta for a new Star Chamber.

Bush officials have defended the order by citing the US Supreme Court's approval of President Roosevelt's decision in World War II to have Nazi saboteurs, captured as they sought to smuggle explosives into Florida, tried and sentenced to death by a secret military tribunal.

But there are fundamental differences in the two cases. Congress had declared war on Germany, making Germans "alien enemies" as a matter of war. And these alien enemies were entering the country illegally, with illegal weapons. They were properly tried as foreign combatants engaged in acts of war.

Today, Congress has not declared war against any nation, nor was it even consulted about the administration's plan to impose martial law.

The president bases his authority for this order only on his own previous executive order proclaiming a state of emergency. And these military courts can try not just persons legally recognized as "alien enemies," but also lawfully admitted, long-time resident aliens from countries at peace with the US. They can do so, moreover, on the basis of evidence far more flimsy than the government had against the Nazi agents. These steps go well beyond what the Supreme Court has endorsed.

It is true that during the Civil War, Abraham Lincoln imposed martial law even in areas of the country far removed from actual combat. The Supreme Court, however, found those actions unconstitutional. The administration "distinguishes" that case because the defendant was a US citizen, and these measures apply only to foreign nationals.

That argument shows that the real basis on which the Bush officials seek to defend these measures is not the power to wage war. Again, we are not legally at war. They appeal instead to what are longstanding, albeit repugnant, judicial rulings holding that aliens have no meaningful rights that can restrain the US government. The logic is that aliens are guests, invited on terms that we can change. If they don't like what we're doing, they can leave. Or we can make them leave.

That analogy may have some appeal, but the decisions that wrote this reasoning into law do not. Judicial denials of rights to aliens originated in response to the US claim in the late 19th century that it could prevent the return to the US of formerly resident Chinese aliens to whom it had guaranteed the right to reentry. Legislators and courts defended this on racist grounds: People so different could be kept out regardless of their apparent rights.

The notion that noncitizens really had no meaningful rights was further underscored after the Spanish-American War, in which the residents of the new US colonies were deemed ineligible for constitutional protections. Again, the legislators and courts held they were too racially distinct and inferior to merit such guarantees.

That sort of racism is, fortunately, disavowed today. But the repugnant legal doctrines denying even basic rights to aliens remain.

Hence Attorney General John Ashcroft believes he can reason in similar ways. He has declared that the people who would be tried in the new military courts do not "deserve" constitutional rights.

But perhaps the most admirable feature of the US Constitution is that it defines most of the fundamental rights it delineates as rights of "persons," not of citizens. "Persons," not citizens, are entitled to protection against unreasonable searches and seizures, against losses of liberty without due process, against denials of equal protection. Persons can forfeit some of those liberties, but only as the result of governmental proceedings in which their constitutional rights are protected throughout. There are no provisions for executive officials to decide unilaterally, in advance of any proof of guilt, which people are and are not "persons" who "deserve" to have such rights.

There are no such provisions for a very good reason: The US began committed to the principle that all persons were endowed with certain inalienable rights, and that governments were created to secure these rights. The founders of this country had a name for executive officials who decided, on their own authority, that some persons actually had no claim to such inalienable rights. They called them tyrants.

So should our courts, and so should we, today.

Rogers M. Smith is a professor of political science at the University of Pennsylvania.