Because that which involved Iraq is intertwined with ongoing investigations into a global proliferation network whose reach we have not yet determined, and which may yet require some covert diplomatic and or military creativity on our part, which is likely to be more successful if done by surprise. By releasing info we have on Iraq we could inadvertantly tell others what we know about their activities, giving them time to prepare.
Then what actions do we have at our disposal should the investigations lead directly to a peculiar country that's pushing global proliferation? We know Russia is supplying missiles, Germany and France are in on helping Iran to build their nuclear facilities. Then what? Bush has a news conference and 'out's' those countries with evidence to what is already known? The world doesn't care. They are too consumed by self preservation and the almighty dollar to say boo to a ghost.
It appears that the US is only one of a limited few countries on the planet that has the balls to put it's neck on the line to try to prevent a nuclear armageddon.
By releasing info we have on Iraq we could inadvertantly tell others what we know about their activities, giving them time to prepare.
Time to prepare for what? They already know we know. That hasn't slowed down from anything that I can tell. If I remember correctly, Russia has sold China about four of those cruise missiles.