The vast majority of immigration laws that are enacted in this country are passed by the federal government or are executive orders. This makes sense, as immigration is dealt with at the federal level, but that doesn't mean that states can't and don't pass their own immigration laws. When they do, however, states may find themselves in federal court defending what individual litigants consider to be a violation of federal law or the Constitution.
And that is what happened to South Carolina after a federal judge recently struck down most of the state's immigration law as infringing upon the federal government's territory. While he has allowed the most controversial aspect of the law -- a measure that allows law enforcement to check individuals' immigration statuses -- many of the provisions can no longer be enforced.
Unfortunately, states like South Carolina have enacted legislation that makes it incredibly difficult to be an immigrant. Although some people may suggest writing off these kinds of laws, these laws often empower police and members of law enforcement to more easily look into individuals' immigration history. If they find something they don't like, an immigrant could be turned over to the federal government for an intrusive investigation.
Ultimately, the laws that govern how people can immigrate to the country, what is considered a deportable offense and the various immigration statuses are federal ones. States like South Carolina, however, may try to pass laws that make it easier to harass immigrants or dig into their lives.
Source: The Associated Press, "SC ordered to pay $98K in fees in immigration suit," Meg Kinnard, July 8, 2014