One of the most admirable elements of British democracy is its incessent open-airing of thoughts, requests, and complaints. But Andrew Sullivan makes an essential point—in light of Joe Wilson’s interruption of Obama’s joint session—on the limits of such exchanges within this kind of legislative body:
[O]ne thing you are not allowed to shout in the Commons is that another speaker is a liar. A lot of circumlocutions evolved to bypass this - “terminological inexactitude” is my favorite (Churchill, of course) - but the ban is for a reason. Once the opposition starts yelling “You lie!” they have essentially abandoned the deliberative process, by questioning the good faith of a speaker. Without an assumption of good faith or a factual rebuttal, just calling someone a liar abolishes the integrity of the debating process. It ends a conversation. And parliament is about conversation.