After Sept. 11, a Legal Battle Over Limits of Civil Liberty

In the fearful aftermath of Sept. 11, Attorney General John Ashcroft vowed to use the full might of the federal government and "every available statute" to hunt down and punish "the terrorists among us."

The roundup that followed the attacks, conducted with wartime urgency and uncommon secrecy, led to the detentions of more than 1,200 people suspected of violating immigration laws, being material witnesses to terrorism or fighting for the enemy.

The government's effort has produced few if any law enforcement coups. Most of the detainees have since been released or deported, with fewer than 200 still being held.

But it has provoked a sprawling legal battle, now being waged in federal courthouses around the country, that experts say has begun to redefine the delicate balance between individual liberties and national security.

The main combatants are the attorney general and federal prosecutors on one side and a network of public defenders, immigration and criminal defense lawyers, civil libertarians and some constitutional scholars on the other, with federal judges in between.

The government's record has so far been decidedly mixed. As it has pushed civil liberties protections to their limits, the courts, particularly at the trial level, have pushed back, stopping well short of endorsing Mr. Ashcroft's tactics or the rationales he has offered to justify them. Federal judges have, however, allowed the government to hold two American citizens without charges in military brigs, indefinitely, incommunicado and without a road map for how they might even challenge their detentions.

In the nation's history, the greatest battles over the reach of government power have occurred against the backdrop of wartime. Some scholars say the current restrictions on civil liberties are relatively minor by historical standards and in light of the risks the nation faces.

The current struggle centers on three sets of issues. People held simply for immigration violations have objected to new rules requiring that their cases be heard in secret, and they have leveraged those challenges into an attack on what they call unconstitutional preventive detentions.