There is a sign over Route 50 that I see everyday when I am driving home from work. It's one of those electronic signs, the kind on which public interest messages are displayed. You know the ones I'm talking about. They usually advise of traffic snarls ahead, although in my experience it is people slowing down to read the signs who create most of the snarls.

Anyway, this sign usually has a message advising that people who see "suspicious" activity should call a "1-800" number and report it. Presumably, although it is not further clarified, this means suspicious activity, which might be related to terrorism or homeland security threats.

Now, I think the fact that someone is trying to get the general public involved in this "war" on terror is a fantastic thing. There is a general sense of complacency setting in across the country that I find very disturbing. Hysteria is not helpful. A healthy sense of vigilance would be.

Still, every time I see that sign I cannot help but wonder. What exactly qualifies as "suspicious"? And, how helpful is a sign like that to the average person without some sort of public campaign, which would educate the average citizen to what they are looking for?

I have spent most of my adult life working counter terrorism. Based on that I have a fairly clear idea in my own mind of the kind of indicators that would suggest that terrorists are preparing an attack. That doesn't make me a genius. It just means I have a lot of experience in a particularly arcane speciality. I doubt that most average (read normal) people have the same list running around in their heads.

The last Al Qaeda attacks on US soil were carried out by a small group of very select individuals. They had been recruited and trained specifically for the operation they carried out, the 9/11 attacks. Among other things, they had lived for long periods in the West and were very comfortable with living and working outside the Middle East. They dressed in Western clothing, observed Western customs and conducted all of their pre-attack planning according to some very specific and very careful methodology.

One would expect that the next attacks, when they come, will be at least as carefully prepared. It is not unreasonable to expect, in fact, that they will be more well crafted. They may, for example, be conducted by operatives, who, while Muslim, do not fit the stereotype of what most Americans expect Muslims to look like. They may be converts from within the United States or Europe. They may be from the Balkans.

However they are put together, the next attacks, if they are directed by Al Qaeda will not be crude, amateurish affairs. Stereotypically "Arab" individuals in traditional dress will not loiter across the street from the target in the days preceding an attack. Individuals speaking broken, accented English will not drive up to security gates of military installations or nuclear power plants and make alerting inquiries. Target selection, casing and evaluation will be carried out over an extended period of time via slow, patient, carefully thought out means.

Will there be indicators that the average citizen can detect? Yes, but only if a process of education enables them to do so. A sign over the highway is a good first step, and one I applaud. Let's follow it up with the necessary continued public information campaign to allow the population as a whole to assist in their own protection.

Like many folks, I have been reading with great interest over the past week about efforts by the Homeland Security and Intelligence Division of the Maryland State Police to monitor the activities of a number of local peace and anti-death penalty groups. I know from personal experience how difficult it is sometimes to really understand what is going on in regard to developments in the intelligence and security realm from reading the paper. The information available to the public is often incomplete and inaccurate. That said, having taken the time to read most of what has been written and having looked at the raw reports from the State Police, which are now available online, I am puzzled.

There has been a lot of talk about the civil liberties implications of this activity. I agree wholeheartedly with most of the concerns. The lifeblood of this democracy is the often unruly, free flow of speech and opinions. I think we ought to be very, very careful about domestic spying, and, when in doubt, I think we ought to err on the side of not doing it.

That said, my immediate concern here is more practical. We are in the middle of a worldwide struggle with a psychotic fringe element of Islam. This is a group that wants to hijack the entire faith, banish all Western influences and drag the entire Islamic World back into the Dark Ages. They are prepared, as they have demonstrated many times, to kill as many people as they have to, in as horrific a fashion as they have to, to carry out these aims. They regard us as their chief enemy, and the major impediment to their achieving their goals. They have hit us many times before. They will hit us again.

This is a real threat. It is not going away, and when you combine it with concerns about the spread of advanced technology and the proliferation of chemical, biological, radiological and nuclear weapons, it is truly terrifying.

What do peace groups and death penalty opponents have to do with any of this?

One of the prime targets of the State Police undercover operations was a gentleman named Max Obuszewski. Mr. Obuszewski, who I assume to be an American citizen of Eastern European descent, is a well known peace activist and pacifist. He believes strongly in the principle of civil disobedience. He has no record of violent activity nor of support for violent activity. You may agree with his politics. You may not. I think you have to admire his commitment.

How exactly is surveillance and infiltration of groups composed of individuals like Mr. Obuszewski going to take anybody in the direction of heading off the next 9/11? I have no doubt that the individual officers carrying out the operations in question did so with the best of intentions, and, frankly, a fair reading of their reports shows a calm, professional and detached approach. That said, how exactly were these operations going to make the citizens of Maryland safer?

Do we know what we are looking for, or are we just looking?

A few months ago I went up to New York City on the train with my cousin for some meetings concerning a book project with which we were involved. We bought the tickets online, caught the train at BWI and got off at Penn Station in Manhattan. It was a low-key, painless procedure and one that many readers of this blog have experienced.

I was shocked.

I spent most of the time from late 2001 through the summer of 2006 deployed to South Asia, Iraq and the Persian Gulf. I didn't think about it until afterward, but when I stepped on to the train for the trip to New York City, it was, in fact, the first time I had been on a train in the United States since before 9/11. How, I thought as I sat there looking around, was it possible that seven years into the "War on Terror" there were no visible changes of any kind to security on passenger trains in the United States? There were no security checkpoints, there was no screening of bags, there was not even an armed security presence to at least give the feel that someone was paying attention to what was happening. There was in short on impediment of any kind, no matter how small, to any terrorist attempt to stage an attack.

On March 13, 2003, a bomb went off in a train in Mumbai, India as it pulled into a station. It killed ten people and wounded seventy others. On July 7, 2005 a series of coordinated bombings struck trains in London. Fifty-two people died. Seven hundred were injured. On March 11, 2006 another series of coordinated bombings struck commuter trains in Madrid. One hundred and ninety-one people were killed. One thousand seven hundred and fifty-five were wounded. Mumbai was struck again on 11 July 2006. This time seven bomb blasts on trains over an eleven minute period left two hundred and nine dead and seven hundred wounded. Is it going to be a big surprise to anyone when the next target of such attacks is a major American city?

The guys we are fighting in this war are many things. Ruthless. Vicious. Evil. They are also smart, dedicated and adaptable. On 9/11 they succeeded not only in finding a way through our airport defenses but, actually, in a very sick, brilliant way of using our own procedures for dealing with in air hijackings against us. Now that we have spent billions on beefing up airport defenses and tightening procedures, the chances that terrorists are going to try some sort of frontal assault on those defenses is virtually nil. If we relax and leave them an opening, they will return to that methodology in a heartbeat. Until then, they are going to keep walking the perimeter, analyzing and planning and looking for what we have neglected.

We can't win this war by closing doors after terrorists have walked through them. At some point, we have to get ahead of the curve and one step ahead of the terrorists. Let's hope we do that with our rail system before we follow in the wake of Mumbai, Madrid and London.