Webster's dictionary defines terror as an "intense, overwhelming fear," and a terrorist as someone who has the ability to "instill intense fear." By that standard, the anthrax scare the past few weeks has been as powerful an act of terror as the attack on Sept. 11th. The nation was terrified by the airliners that slammed into the World Trade Center and Pentagon, killing more than 5,000 people. The assault of anthrax-laced letters has caused insignificant casualties by comparison — three dead, a couple of people seriously ill, a handful sick but recovering, and fewer than 50 slightly tainted — but it has created a terror in this country no less intense and widespread than what erupted on Sept. 11th.

[an error occurred while processing this directive]First, consider the practical effects: The anthrax threat has disrupted the nation's paper communications system as successfully as a super cyber-virus might affect the Internet. Then there's the psychological aspect: Terrified mail handlers are wearing rubber gloves. Office workers are afraid to open any letters. News organizations have closed their mailrooms. Government agencies and legislators are leaving constituent mail in bags. Pranksters are taxing first responders so heavily that frustrated law enforcement officers are threatening to put perpetrators in jail for life if they catch them. Hazmat teams are being rushed here and there to scoop up what most of the time turns out to be spilled coffee creamer, salt, dirt, or baby powder.

On Capitol Hill, all that fear has made history: No war — not World War II, not World War I, not the Civil War, not even the War of 1812 when British forces burned the White House— has resulted in the U.S. Congress being evacuated. But it's just happened twice: After the attacks on September 11th and again last week.

(Let me back up a second here for the sake of historical accuracy. During the Civil War, Congress was not in session during the times Washington was in danger of attack by Confederate forces so there was no need to evacuate. Ditto for the War of 1812. Congress was out of session when the British stormed Washington on Aug. 24, 1814. And Congress hadn't technically convened on Sept. 11th even though folks were cleared out of the Capitol. But you get the picture.)

The terrorist — or terrorists — who attacked with envelopes full of anthrax powder turned out to be as savvy and sophisticated as the ones who hijacked four U.S. airliners full of jet fuel. In a world whose circadian rhythm is now set by the 24-hour news cycle, the anthrax attacker(s) knew — or maybe they've now discovered — that the best way to create an instant media frenzy over terror was to send the deadly letters to the media.

And they quickly discovered that the best way to strike terror and confusion within the U.S. government was to send the contaminated mail to a Congress that can't agree on anything even in the best of times. Be calm, our leaders told us. No need to panic, they insisted. But to a jittery America those pleas sounded like the orchestra that kept playing after the Titanic hit the iceberg.

House Speaker Dennis Hastert and Minority Leader Dick Gephardt looked the worst last week, recessing their chamber early so technicians could sweep their side of the Capitol complex for traces of anthrax. They're still furious at Senate Majority Leader Tom Daschle, who received the anthrax- laced letter but announced that terrorists wouldn't scare the Senate into recessing early. (Hastert and Gephardt insist that Daschle reneged on an agreement the House and Senate leaders had at the beginning of last week to quit early. Daschle insists he never made such an agreement. Just for the record, Senate Minority Leader Trent Lott is standing behind Daschle.)

The caution Hastert and Gephardt displayed was vindicated somewhat when the environmental sweep turned up traces of anthrax in a House mailroom and, tragically so, when two District of Columbia postal workers died, perhaps from handling the Daschle letter, or other letters posted to members of Congress. Though six congressional office buildings remained closed for anthrax testing, the Senate went back into session on Tuesday with House members hard on their heels.

The FBI, which scrambled to catch up with the Sept. 11 attack, now scrambles to catch up with the anthrax attackers. Agents still clung to the theory that it's a nut job — a deranged individual or a homegrown group with a grudge to settle, perhaps squirreled away in a seedy room in New Jersey. But that's still just a theory, chipped away almost hourly by new reports of suspiciously high grade anthrax.

The bottom line, officials keep telling us, is that investigators just don't know who's behind this attack. And this uncertainty, of course, is probably just what the terrorists were hoping for.