Why would the US Supreme Court overturn a state law?

The US Supreme Court only reviews state laws that are appealed through the court system on the grounds that they conflict with federal law or infringe rights protected by the Constitution. The primary considerations for using judicial nullification to overturn state laws would be:

  1. if they infringe individual liberties protected by the Bill of Rights;
  2. if they conflict with a federal law or treaty; or
  3. if they usurp a power reserved for a branch of the federal government.