The bomb exploded at 4:40 p.m. Minutes earlier I had walked across campus to deliver a manuscript -- a labor of love -- to my publisher, Yale University Press. It had been a triumphant moment. My first thought at the sound of the blast: At least I finished the book before Osama bin Laden finished me!

The nation was on "orange" alert. I braced for the terrorists' second strike. But nothing followed except an ear-splitting emergency alarm.

So down the main staircase I rushed -- past the smoke-filled classroom, through the majestic corridor that was eerily quiet and entirely intact. I was soon standing in the open, surrounded by soaring Gothic spires, and the mock-heroic aspect of the enterprise overwhelmed me. This tiny explosion was obviously an amateur operation: no injuries, no structural damage. But thanks to the orange alert, it was sure to be transformed into yet another (minor) battle in the war on terrorism.

In putting the nation on high alert back on May 20 -- several days ago, the country's alert level was lowered back to "yellow" -- the Department of Homeland Security publicly stated that it lacked any credible evidence of an imminent attack. Nor did it offer any concrete advice to the public. To the contrary, it explicitly encouraged people to continue with their Memorial Day celebrations as if nothing were amiss.

And yet the national news media descended on New Haven, Conn., and reported the blast far and wide. Despite official statements downplaying the incident, millions throughout the world quickly heard about the attack. Soon enough, I was receiving a host of e-mails from foreign parts anxiously inquiring after my fate. I was touched, but oddly oppressed with my new role as a prop in a media event.

We are manufacturing a culture of fear. The Homeland Security Department has every incentive to put the nation on alert lest an attack catch it flat-footed. National news organizations have every incentive to transform any incident into the biggest ongoing story of the decade. It is time to call a halt to this cycle. Unless the Homeland Security Department has real evidence pinpointing particular targets, it should keep its anxieties to itself.

Last year there were 16,000 murders in the United States. Yet the FBI doesn't issue orange alerts in response to chatter on gangland cell phones threatening an escalation of murderous hits; it simply beefs up its activities in sensible ways. We should expect the same of the Homeland Security Department. If anything, these public pronouncements may cause more harm than good: If and when the Yale bomber is caught, will we learn that the orange alert encouraged him or her to choose this moment to prey on the nation's fears?

Beyond the workings of sickened minds, there is a larger point. We are creating cycles of public anxiety that have no relationship to the real world. The State Department recently reported that there were 199 international terrorist incidents in 2002; that's down from 355 in the previous year and the lowest since 1981. And yet this hasn't made the slightest impression on the public, which follows the incessant reports of color-code changes with escalating anxiety.

We do face grave dangers. The balance of technology has shifted, allowing small bands of angry men and women to wreak great havoc. This threat justifies serious and sustained countermeasures. But however hard it may be, we should be learning to live with our problems without losing a larger perspective. Rather than stoking our collective fears, the Homeland Security Department should be committing itself to old-fashioned American pragmatism, a sober determination to consider the specifics of specific problems. This has been the British approach. Despite 30 years of Irish Republican Army terrorism, the British have refused to develop a system of public alerts that only generate free-floating anxiety.

We are living during the calm before the next storm. Our Homeland Security Department will not be perfect. We may stop 99 out of 100 terrorist attacks, but we will not stop them all. The way we think and talk now will shape the way we act in the future. If we allow ourselves to be swayed by orange alerts today, we will be caught up in a whirlwind of fear tomorrow. There has never been a better time to recall Franklin Roosevelt's great first inaugural address, the one where he said, "The only thing we have to fear is fear itself: nameless, unreasoning, unjustified terror . . ."

Bruce Ackerman is a professor of law and political science at Yale University.