As a Libertarian and someone who is not religious I have to take your side on this issue, which may come as a surprise. I don't believe that it's possible or desirable to keep religious beliefs out of politics. In fact Christians are natural Libertarians (see the excellent post on my home page, "Is Jesus A Libertarian?") Libertarians object only to using government power to force religious beliefs on others.
No, it doesn't. I really don't have anything against libertarians or Libertarians. I like Ron Paul quite a bit. Sometimes when I'm feeling really ticked at the stupidity of the GOP, I'll tell my fellow Republicans I going to bolt to the Ls. Maybe one day I even will.
Plans of salvation are in no way the government's business but all nations need a common morality if they have any hope to survive.
Jefferson and Franklin -- neither of whom believed in the Resurrection -- both vocally believed our values should be based on the teachings of Jesus. For most of our history they were.
I, of course, believe in the Resurrection but it would be an act of great evil to make this belief -- or any belief -- a requirement for citizenship.