According to a September 6, Salon.com article by Sidney Blumenthal, there was a briefing that George Bush received from George Tenet on September 18, 2002, that no one else received. At that briefing Bush was told that Saddam Hussein had no weapons of mass destruction. George Bush dismissed the information, saying that the source, an Saddam's foreign minister, Naji Sabri, and a member of Saddam's inner circle, was wrong.
Tenet never brought the information up again, and it was excluded from the National Intelligence Estimate of October 2002, which claimed that there were WMD in Iraq and prompted the Congressional vote to give Bush authority to use military force. According to Blumenthal this information was not even circulated within the CIA among those agents involved with proving or disproving whether Iraq had WMD. It simply "went away".
The former CIA chief of clandestine operations for Europe, Tyler Drumheller, told the Tenet/Sabri story to "Sixty Minutes" last year (aired on April 23, 2006) but now two former CIA officers directly involved in this intelligence have also come forward and confirmed the story with Bluementhal that the CIA had received quality and documented intelligence from Sabri that Iraq had no WMD.
George Tenet never shared that information with the military personnel planning the invasion, nor with Collin Powell who ended up making a fool of himself in front of the United Nations in February 2003. Instead Bush and company pursued their source, Curveball, and ignored the work and report that the CIA officers, working the Sabri allegation, had done.
Go pour yourself something strong to drink, read the story, and put impeachment back on the table.