During the Clinton presidency, Rush Pumpkinhead started each show with the day count for "America Held Hostage." The implication was that Bill Clinton seized an unwilling country, and now Republicans are similarly treating Obama's presidency as illegitimate. First, birthers claim he's truly illegitimate by challenging his birth certificate and his well-documented accounts of his own origins, while others have attacked him as a socialist and a Nazi out to undermine the American way of life. When he proposes to speak to schoolchildren to "challenge them to work hard, set educational goals, and take responsibility for their learning," many Republicans around the country see this as something suspicious - perhaps an occasion for indoctrination from the dark side.
The premise is absurd, but it's further evidence of Republicans' efforts to reduce American politics to a Holy War - a clash not of reasoned, evidence-based notions about what's best for the country but simple belief. Belief is the central tenet of Christianity - that you accept things you can't see, take them on faith, and act as if they're true. Over and over, Republicans retreat to this position, whether on large matters like the unquestionable rightness of the free market, or on specific issues like the non-existent "death panels" and the non-existent threats to seniors posed by health care reform. They choose to believe regardless of what evidence says to the contrary, and those who don't are heretics, spiritual outlaws whose ideas should be criminal because of the threat they pose to America as Republicans believe it to be.
Politics as Holy War can't be laid solely at the feet of Conservatives. Cable network news has long had an investment in a clash of the ideologues. After Michael Kinsley left CNN's Crossfire, Christopher Hitchens says he was asked to take his place on the left debating Pat Buchanan. He passed, he says, when he found out that his job wouldn't be to take the liberal position but to defend Clinton no matter what. And the Holy War fervor has prompted some Democrats to push back reflexively and others are equally automatic in the belief in their own rightness.
Still, it's instructive to remember that the one president whose claim to the White House was genuinely questionable was never treated by Democratic legislators as illegitimate or a criminal, and though his speech gave listeners reason to question his wisdom and his arguments for war in Iraq were as much propaganda as policy, he was never treated as an enemy of the state by the opposition. (The irony is that he was one. With the Patriot Act, he did more long-term damage to the American way of life than terrorists ever could. 9/11 was a remarkable success in that it scared the Bush White House and American government into changing itself in ways no outside force ever could.)