History makes clear that when this nation goes to war, there is a serious danger that the government will respond by going to extremes, trampling important legal protections for its citizens. Recent events confirm that the war on terror is no exception. But there is another danger when an emergency arises: Vigilance can weaken, leaving Americans exposed.

In some ways, our leaders overreacted to the Sept. 11, 2001, attacks. But even today, they are also underreacting to tomorrow's threats.

The Bush administration was forced to abandon one mistake last week when it endorsed Arizona Republican Sen. John McCain's legislation banning "cruel, inhuman or degrading treatment" of detainees abroad. Vice President Dick Cheney had lobbied senators to modify the bill, arguing that harsh methods were sometimes needed to extract information from terrorists.

But the administration's endorsement of such tactics created serious conflicts--with the obligations America accepted in 1994 by ratifying the international convention against torture; with the public's sense of right and wrong; and with the demands of European allies whose cooperation is needed in the war on terror. Thursday, the president invited McCain to the White House and agreed to nearly everything the former POW demanded.

That change of policy coincided with a disturbing revelation in Friday's New York Times. The newspaper reported that shortly after Sept. 11, the president gave the National Security Agency secret permission to monitor the international communications of people inside the United States without court approval. That is a drastic departure for the NSA, which normally conducts such surveillance only overseas.

This may also be a violation of American law, which requires that a special court issue warrants for wiretaps on communications originating in the United States. Some officials familiar with the program said it is illegal. But a Justice Department memo took the radical position that the congressional resolution authorizing the president to act against Al Qaeda enabled him to use methods that were previously forbidden.

On Saturday, President Bush strongly defended the program, saying it has "helped detect and prevent possible terrorist attacks" here and abroad. Had the administration really believed it had congressional consent for spying on Americans at home, it could have asked for legislation to affirm that. It didn't, for the obvious reason that Congress would not have agreed.

This disclosure had the regrettable effect of helping to at least temporarily derail reauthorization of the USA Patriot Act, which for the most part represented a careful and prudent response to the new challenges posed by Al Qaeda. On Friday, Senate opponents managed to prevent a vote on the bill, leaving in limbo some provisions scheduled to expire Dec. 31.

While fear produced some abuses, it has not prevented the onset of complacency in the face of an ongoing threat. Earlier this month, former members of the Sept. 11 commission issued a dismal "report card" giving Congress and the president 5 F's and 12 D's in their handling of such matters as airline cargo screening, communications among first responders and allocation of homeland security funds.

Excesses of enforcement violate civil liberties. Lapses of vigilance can lead to mass carnage. Our leaders have an urgent duty to correct both mistakes, without delay.

Copyright © 2005, Chicago Tribune

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