Since 1998, his efforts to reconstitute his nuclear program have been focused on acquiring the third and last component: sufficient fissile material to produce a nuclear explosion. To make the fissile material, he needs to develop an ability to enrich uranium. Saddam Hussein is determined to get his hands on a nuclear bomb.

He is so determined that has made repeated covert attempts to acquire high-specification aluminum tubes from 11 different countries, even after inspections resumed. These tubes are controlled by the Nuclear Suppliers Group precisely because they can be used as centrifuges for enriching uranium.

By now, just about everyone has heard of these tubes and we all know that there are differences of opinion. There is controversy about what these tubes are for. Most U.S. experts think they are intended to serve as rotors in centrifuges used to enrich uranium. Other experts, and the Iraqis themselves, argue that they are really to produce the rocket bodies for a conventional weapon, a multiple rocket launcher.

Let me tell you what is not controversial about these tubes. First, all the experts who have analyzed the tubes in our possession agree that they can be adapted for centrifuge use.

Second, Iraq had no business buying them for any purpose. They are banned for Iraq. I am no expert on centrifuge tubes, but this is an old army trooper. I can tell you a couple things.

First, it strikes me as quite odd that these tubes are manufactured to a tolerance that far exceeds U.S. requirements for comparable rockets. Maybe Iraqis just manufacture their conventional weapons to a higher standard than we do, but I don't think so.

Second, we actually have examined tubes from several different batches that were seized clandestinely before they reached Baghdad. What we notice in these different batches is a progression to higher and higher levels of specification, including in the latest batch an anodized coating on extremely smooth inner and outer surfaces.

Why would they continue refining the specifications? Why would they continuing refining the specification, go to all that trouble for something that, if it was a rocket, would soon be blown into shrapnel when it went off?

The high-tolerance aluminum tubes are only part of the story. We also have intelligence from multiple sources that Iraq is attempting to acquire magnets and high-speed balancing machines. Both items can be used in a gas centrifuge program to enrich uranium.

In 1999 and 2000, Iraqi officials negotiated with firms in Romania, India, Russia and Slovenia for the purchase of a magnet production plant. Iraq wanted the plant to produce magnets weighing 20 to 30 grams. That's the same weight as the magnets used in Iraq's gas centrifuge program before the Gulf War.

This incident, linked with the tubes, is another indicator of Iraq's attempt to reconstitute its nuclear weapons program.

For me, it comes down to Iraq's behavior. Iraq gave little reason for others to believe its statements that it had ended its prohibited weapons and missiles programs. It was still importing prohibited materials (as the aluminum tubes were even if they were only for rockets) in contravention of the UN sanctions. It never, as the UN demanded, fully accounted for the materials it claimed to have destroyed. It was still playing games with the inspection process - not giving a full accounting, threatening scientists with death if they were interviewed, etc.