No, Bleu. This does not mean every American must have a religion, it simply means that our representatives do not have to hide their religious viewpoint from the public. It means that we refuse to tilt at windmills (like Newdow constantly does) such as the suit to try to stop President Bush's speaking about Jesus Christ at his official appearances.
I would appreciate an politician who honestly says he's an agnostic over one who simply mouths crowd-pleasing pieties (I'm not saying that Bush does that, but some do). I've known athiests and agnostics who lived up to the Golden Rule a lot better than many Christians. Check out the death threats against Newdow on another thread to see what I mean.