As a rule, they're not. That's because we live in a secular country, with a secular system of government. What I'm saying is, let's keep it that way. Do you agree?
Well, maybe you're not familiar the Dominionist or Reconstructionist movement, which seeks to make the United States a Christian theocracy, in which all religions other than conservative Christianity would be banned, and Biblical law would be the law of the nation? You can read more about them
here.
It's about a movement that seeks much more than that, a movement that wants to make the U.S. a country in which their brand of Christianity is mandatory, in which Wiccans would be executed, sodomy punishable by death, and so forth.
The battles now are being fought over things like ten commandment monuments on courthouse lawns, mandated teaching of creationism a.k.a. intelligent design, Air Force Academy officers pressuring cadets to convert to Christianity, and other issues.