The portion of Attorney General John Ashcroft’s proposed anti-terrorism bill that has attracted the most controversy since it was made public on September 19-the so-called "indefinite detention provision"-may turn out to be less far-reaching and less controversial than it first appeared. Therein lies a lesson about how best to reconcile Ashcroft’s urgent request for new powers with Congress’s need to deliberate carefully on this complex and multifaceted bill before passing laws that could be with us for decades.

Section 202 of Ashcroft’s September 19 "discussion draft" appears on its face to mandate arrest and incarceration for indefinite periods-weeks, months, even years-of any noncitizen whom the Attorney General has "reason to believe may commit, further, or facilitate" terrorist acts or "engage in any other activity that endangers the national security of the United States." The government would not need to show that the detainee was probably a terrorist. And judicial review would be so tightly restricted as to be illusory for most of those incarcerated.

This language, which Ashcroft initially pressed Congress to adopt by September 21, provoked criticism by a wide swath of legislators and civil liberties groups. Understandably so: Whether or not this action is warranted by the unprecedented perils we face, the idea of indefinite detention based on mere suspicion smacks of police statism. And it is not hard to imagine thousands of noncitizens uninvolved in terrorism being locked up for months simply because they looked suspicious to some bureaucrat.

But then Ashcroft indicated (in his somewhat cryptic September 25 Senate testimony), and another official confirmed (in a detailed September 26 interview with me), that the Administration’s intent is to authorize detention of foreigners deemed dangerous only if the government begins deportation proceedings within five days of their arrest by formally charging them with immigration-law violations. The Justice Department is redrafting Section 202 to make this clear, the official said.

Current law already provides for pretrial detention of noncitizens charged with terrorist crimes. What Section 202 is designed to add, says the official, is the power to detain noncitizens suspected of terrorist intent if-and only if-they are also charged with immigration violations. Even assuming that the new language will make this crystal clear, it will still trouble some critics: Trifling or unproven immigration violations could be used as pretexts to detain innocent people based on mere suspicions of terrorist designs during protracted removal proceedings. But that’s less troublesome than the specter of long-term detention of people charged with no illegal conduct at all.

It’s not hard to see why the Administration wants as much power to detain suspected terrorists as our constitutional traditions can stand. Consider the unprecedented problem that may well be presented by some of the more than 350 people the Justice Department has already arrested or taken into custody for questioning. Let’s assume, plausibly enough, that on closer inspection, many of those arrested prove to be entirely uninvolved in terrorism or other illegality; that the government finds enough evidence to charge many others with immigration violations or crimes, perhaps including complicity in the September 11 mass murders; and that the available information about still others (let’s say 20 of them) would leave a reasonable prosecutor or judge thinking: "This man is probably no threat, but there’s maybe one chance in three, or four, or five, or ten that he’s a terrorist bent on mass murder."

What should the government and the courts do with the people in this last group? With, say, a (hypothetical) Pakistani chemistry major at a university in Chicago who had downloaded articles about how terrorists might use small planes to start an anthrax epidemic and had shown an intense but unexplained interest in crop-dusters? Or with a (hypothetical) Egyptian tourist arrested on a Boston-bound Amtrak train after the FBI had found in his luggage-through a search of doubtful legality-$8,000 in cash, an Islamic Jihad pamphlet, and two box cutters? Or with a (hypothetical) Iraqi refugee who had been photographed at a Beirut restaurant frequented by followers of Osama bin Laden, had recently toured the Capitol three times during a one-week trip to Washington, and had left in his motel room a news article detailing how terrorists might succeed in smuggling explosives into government buildings?

Under long-established constitutional law, the government would have to release all of these men after a few hours-or at most, days-of questioning and investigation, unless it had enough evidence to charge them with some kind of crime or deportable offense, or could show them to be "material witnesses" likely to have evidence of crimes and to disappear if released.

Should Congress give Ashcroft the new detention power he now seeks? Well, it should first take a hard look at the revised language. If it is clear, and if Ashcroft insists that he urgently needs the new detention power to avert a clear and present danger of more mass murders, Congress should give it to him. But it should attach a six-month sunset provision. The reason is that it would take months-rather than the 30 days that I unrealistically suggested in an earlier column-for Congress to hold hearings, to give careful consideration to the case for and against the proposed detention power, and to understand fully its potential impact.

The same is true for many of the dozens of other provisions in Ashcroft’s anti-terrorism bill. Some sections, such as those that would increase penalties for terrorist activities and make it a crime to harbor terrorists, are relatively modest and command virtually unanimous support in Congress. Other provisions, however, are both more far-reaching and more difficult for even expert congressional staffers to evaluate in a hurry, to say nothing of the rest of us. Still others are drafted broadly enough to apply in garden-variety criminal matters unrelated to terrorism. For example:

• Section 201 would authorize deportation of foreigners for supporting the lawful activities (such as charitable work) of any organization that has any "significant subgroup" that has supported activities fitting the broad definition of terrorism. Is this species of guilt by association justified? Let’s hear it debated.

• Section 204 appears to make all of the immigration provisions retroactive. Critics say that would allow for deportation of any permanent resident alien or other noncitizen for having contributed to Nelson Mandela’s African National Congress in the 1980s-even though it was legal for Americans to contribute-because it staged military ("terrorist?") attacks on the apartheid regime. Really? Let’s find out.

• Section 153 would extend the government’s power to obtain wiretap and search warrants without the usual constitutional requirement of probable cause to believe that evidence of crime will be found-by using the special intelligence-gathering powers in the Foreign Intelligence Surveillance Act-even in (say) routine narcotics investigations. The government would need only to allege that evidence of foreign terrorist or intelligence activity might also be found. Is such a major expansion of search-and-seizure powers really necessary? Let’s find out.

• Sections 103, 154, and 354 would significantly lower the longstanding barrier between domestic law enforcement agencies, including the FBI, and foreign intelligence agencies, including the CIA and the National Security Agency. These provisions would provide broadly for sharing of both foreign-intelligence information (gathered without the usual Fourth Amendment protections) and grand jury secrets (which cannot now be given to intelligence agencies without special justification). Necessary? Let’s find out.

• Section 352 would give the government more power to obtain warrants to search homes for evidence of any crime (including crimes of terrorism) without giving the customary notice to the occupants at the time of the search. In addition, Section 406 would expand the government’s already sweeping powers to forfeit the property of people allegedly involved in garden-variety criminal cases having nothing to do with terrorism. Why so broad? Let’s hear the explanations.

• Section 309 would define crimes of terrorism more broadly than ever before-so broadly, critics suggest, as to subject (say) anti-globalization protesters who paint silly slogans on government buildings to onerous penalties that were devised with mass murderers in mind. True? Let’s find out.

In this dangerous new era, when our lives may depend on law enforcement and intelligence agencies working both more effectively and more collaboratively than ever before, such ideas "should neither be hastily enacted nor reflexively opposed," in the words of a Washington Post editorial. Alternatively, if urgency does require hasty enactment of some provisions, a six-month sunset provision to allow for preparation of more considered permanent legislation would do the war against terrorism no harm. And it might do our liberties a lot of good.