Why are most American States terrified of enforcing immigration laws?

I don't get it. Arizona and now South Carolina seem to be the only states putting boot to a.s.s on illegal immigration. Some liberal coward judge in Florida blocked parts of their State's immigration bill saying Cops would be allowed to question suspected illegal immigrants in Florida. Which is basically lengthening what Congress is doing. Why are American states so scared to crackdown? It's pathetic. America will officially tolerate just about anything these days. While we're at it. Can we erase the border with Canada and Mejico and make one big North American country?