The Constitution says that the Fed govt will guarantee to the states, a Republican form of government.
Sharia law ain't.
How does this balance against the Constitution's guarantee that Congress shall make no law preventing the free exercise of religion?
"The social contract exists so that everyone doesn’t have to squat in the dust holding a spear to protect his woman and his meat all day every day. It does not exist so that the government can take your spear, your meat, and your woman because it knows better what to do with them." - Instapundit.com