Updated

What is a smoking gun? Something no doubt many want to see in order to justify going after iraq.

But what happens when you wait for a smoking gun? By that time, the gun has gone off. It's smoking, because it has already done something. Which makes me wonder why only then we react to it.

Smoking guns are final events. They're not starting events.

Sept. 11 was a smoking gun.

Pearl Harbor was a smoking gun.

Hitler going into Poland was a smoking gun.

You see, the act of terror itself is the smoking gun.

What we far more often ignore are the things that lead to that smoking gun.

Like all that Al Qaeda noise and the USS Cole attack prior to Sept. 11.

Like Hitler stomping into lesser countries prior to invading Poland.

Like curious Japanese ship and troop movements prior to Pearl Harbor.

We always manage to connect the dots after they've forceably been connected for us.

History teaches us that it always looks so clear after the fact -- after the smoking gun.

After the Columbia is destroyed in re-entry when there had been plenty of warnings about the tiles. After the Challenger disaster when there had been plenty of questions about launching in cold weather.

We never see it coming up, until everything we know is blowing up. Failing to see that by then, our time is up.

Some say where there's smoke, there's fire. I say, by the time you see the smoke, you've missed the fire. Along with all the other tell-tale signs you refused to see long before the fire.

Watch Neil Cavuto's Common Sense weekdays at 4 p.m. ET on Your World w/Cavuto.