Imagine this press conference: GW Bush: "We found WMD in Iraq. All of our critics have been completely discredited"
Media: Can we see them?

GW - No. you'll just have to take my word for it. We have experts to prove their authenticity.

Media: Can we talk to the experts? Can we interview the people who found the weapons?

Gw: NO. And the mere fact that you are asking these questions proves that you are partisan rumor mongers. End of story. case closed.