The Missouri legislation is perhaps the most extreme example of a states’ rights movement that has been spreading across the nation. States are increasingly adopting laws that purport to nullify federal laws – setting up intentional legal conflicts, directing local police not to enforce federal laws and, in rare cases, even threatening criminal charges for federal agents who dare to do their jobs.

An Associated Press analysis found that about four-fifths of the states now have enacted local laws that directly reject or ignore federal laws on marijuana use, gun control, health insurance requirements and identification standards for driver’s licenses. The recent trend began in Democratic leaning California with a 1996 medical marijuana law and has proliferated lately in Republican strongholds like Kansas, where Gov. Sam Brownback this spring became the first to sign a measure threatening felony charges against federal agents who enforce certain firearms laws in his state.