On the first Fourth of July after 9/11, I was travelling with my family. I avoided staying in Reno, and had radiation detection equipment packed in a small cardboard box in back of my car. I would have bet money that something would hit that day.

There was nothing. We watched fireworks outdoors sitting on a rocky outcropping on a little town on the border of Nevada and Utah. The Union still stood, "rock-bottomed and copper-sheathed," as Stephen Vincent Benet once put it.

One 9/11 anniversary went by. Then another. An Olympics in Utah. More Independence Days. An Olympics in Greece.

Almost three years now.

Nothing. Not even a car bomb. Nothing in America has been attacked. Or Britain. No American embassy. No American cruise ship. No American hotels in other countries. Nothing.

We have been told that America is crawling with terror cells. It's obvious that our borders could be penetrated by a small armed division, never mind individual terrorists in civilian clothes.

While a major act of terrorism like 9/11 might require a lot of planning, and even some resources, how hard would it be to construct a belt bomb somewhere in America and use it? Or do other things that would be even easier?

Where the hell are the terrorists?

There are theories that explain this. One is that our security is damn good. This has some plausibility: there have been arrests around the world, and roundups of actual terror cells. I can buy this.

But there is another theory.

Before the war in Iraq, intelligence agencies around the world were convinced that Saddam has WMD ready to go. Leaders of neighboring Arab nations were convinced of this. Saddam's own generals were convinced that other generals had these weapons.

We get there, and there are no stockpiles. No arsenals. There have been various explanations, all of which have some plausibility. Contraband moved to other nations. Contraband still hidden. But one other theory stands out in this context: That Saddam did his damnedest to convince the world and even his own people that he had weapons he did not possess.

This theory says that Saddam was a fraud. A man standing in front of the cops pointing to a hostage with an outstretched finger in his pocket.

Now, look at al Qaeda, and other terror groups.

What if they are blowing smoke? What if they are mostly a bunch of guys hiding in caves or enclaves in Iran or Pakistan, and talking to their followers and the world about their thousands of recruits, and active cells the world over? How much of what we know about these groups comes from interrogating terrorist flunkies? What would these flunkies be told? That there are al Qaeda forces everywhere ready to strike? Or that the movement was almost annihilated in Afghanistan, and is still picking up the pieces?

I'm not even convinced bin Laden is still alive.

Is America full of cells ready to go? Or maybe just one or two? One such cell took out part of New York City and Washington. Obviously they have not been imaginary. But maybe we made a bigger dent in them than we thought in recent years.

Any other theories out there?

If they are out there in America, what have they been waiting for?