Immediately after 9/11 the Democrats and their lapdog media dug up some intelligence reports that had very tenuous links to indicate there may have been information indicating an attack was imminent. The evidence was very sparse and hardly ammounted to anything that would point to what actually happened. But that didn't stop the certain people from asking "What did Bush know and when did he know it?"
Pre-Iraqi Freedom there were volumes of evidence against Saddam. There was enough evidence of Saddam's weapons of mass destruction to convice Clinton and the Democrats in Congress that a new bombing attack of Iraq was needed in 1998 to stop Saddam. There was certainly enough evidence to convice the UN to pass resolution 1441 and begin new inspections of Iraq. There were violations found by the inspectors and Saddam refused to come clean, choosing instead to continue to hide things from the inspectors.
Post-Iraqi Freedom the media wants to turn things upside down. They say there was no believable evidence. It was all a sham by Bush even though the evidence was there before Bush took office. Even though the same Democrats that refused to accept the evidence presented by the Bush administration accepted it when Clinton presented virtually the same evidence.
Saddam was a credible threat to the US. The threat has been eliminated. The media just can't stand the fact that Bush did what Bubba should have done.