I wasn't really trying to mock him or shut him up, but I really do find his argument ("Well, the CIA lied to Bush!") to be a pathetic one. It's the same as the other common equivocation fallacy employed by Republicans ("Look at this long list of prominent Democrats who voted for the war too!"). The Democrats supported the war based on what they were told by the CIA, which is a wholly-owned subsidiary of the executive branch. Any intelligence analysts who refrained from hopping on board Bush's war wagon did so at peril of their careers.

The whole Iraq war was an exercise in confirmation bias. Congressional Democrats certainly bear their share of culpability, but they also have very good excuses compared to anyone in the Bush administration. In an ideal world with Nuremberg-like tribunals, the Bush insiders would be swinging from gibbets, while we'd let the Democrats off the hook after a few years in Spandau. Claiming that the people you hired lied to you is no defense.