But it is the genius of our constitutional system that its authors anticipated how duty and fear can conspire to push officials to do anything within their power, or beyond it, to respond to such dastardly attacks and prevent their reoccurrence.

The Constitution is based on the idea that no person, no matter how honest or dedicated, can be trusted with powers that no one else oversees. The president's insistence that he has not only the power, but the obligation, to recklessly sweep aside more than 200 years of legal foundations, decide for himself which laws he must abide by - and tell no one - is exactly the kind of abuse the founders sought to prevent.

Last week, four years and one presidential election after the fact, the American people learned that the president has repeatedly allowed the National Security Agency to eavesdrop on communications between persons in the United States and people abroad who are - or so say those doing the spying - connected with terrorists.

The fact that Bush has letters of permission from people who work for him is beside the point. Such authority must be granted by Congress and overseen by the courts.

In 1978, reacting to abuses committed by the CIA, Congress passed the Foreign Intelligence Surveillance Act to set boundaries on such spying. Congress must now revisit that act and determine whether it does enough - or too much - to limit executive branch spying.

At his press conference Monday, Bush was harshly dismissive of the obvious suggestion that he has assumed a power usually associated with dictators. That, and his flat statement that the long-overdue leak of this policy in The New York Times was "a shameful act," suggest that this administration is far too fearful to engage in the kind of democratic governance it is sworn to protect - that it thinks it is protecting.

The groupthink of one branch of government can justify just about anything - torture, secret prisons, unwarranted searches. That is why our system demands that such momentous decisions not belong to one branch alone.

If existing FISA provisions for national security warrants, issued almost without fail by a special court created for that purpose, are too cumbersome, the president has had ample time to ask Congress to change the law.

That he has not done so further undermines the faith that we, and the other branches of government, must have in our executive power, not only in times of trial, but always.