Why Did the US Ignore the IAEA?

The debate between Bush and Kerry over the missing explosives in al-Qaqaa ignores an important issue: why did the administration ignore the IAEA's designation of these explosives as important to a nuclear weapons program? Bush has said that the main reason for the invasion of Iraq was because Saddam had or was about to get weapons of mass destruction, including nuclear. Remember the mushroom cloud smoking gun?

Under those circumstances, the administration should have requested a list of designated nuclear-related sites from the IAEA (the International Atomic Energy Agency) and then specifically assigned US troops to check on and secure those sites. The fact that the ABC News video shows US troops breaking an IAEA seal, having no idea what it was, indicates the poor training the troops got for their primary mission of protecting the US and the rest of the world from WMD.

The explosives were not WMD, but they are an important ingredient in making a nuclear weapon go bang, once you have the really important ingredient, fissile uranium or plutonium. Why weren't the troops briefed on this aspect of the invasion, and why was the IAEA's list of nuclear sites ignored? Partly because of the ill will between the Bush administration and the UN, and the UN's IAEA in particular. Bush singled out Hans Blix, who was heading up the UN's inspection effort, for particular personal insults, and apparently the US spied on Blix in the run up to the war. When you burn your bridges, as the US did before the war, you had better be right. It turns out that we were not right.