In the Huffington Post, Barry Friedman, Jacob D. Fuchsberg Professor of Law, writes:
Kansas recently adopted a so-called "Second Amendment Protection Act." The law provides that Kansans can ignore any federal law that attempts to regulate guns in Kansas if the guns in question were made in Kansas and stay there. It would apply, for example, to a federal ban on assault weapons. Yet more incredibly, Kansas makes it a crime for any federal official to try to enforce federal law against such gun holders. US Attorney General Eric Holder quickly reminded Kansas that under the United States Constitution, the states do not have authority to override federal law.