flat tax debate

Steve Verdon's critique of Kevin Drum's critique of the flat tax is pretty convincing. However, I still lean towards Kevin's analysis because, frankly, I don't trust the Congress to implement the actual flat tax Steve is talking about. As long as insane people like Grover Norquist continue to hold influence over conservative fiscal policies, they have a credibility deficit with me. After all, look what happenned with the Medicare bill... can we trust flat tax legislation to actually make it past the House without being turned into something grotesque (and completely opposite to the clear argument Steve lays out) ?