NY Times 
Match 10, 2013
South Dakota became the first state in the nation to enact a law explicitly authorizing school employees to carry guns on the job, under a measure signed into law on Friday by Gov. Dennis Daugaard.
Passage of the law comes amid a passionate nationwide debate over arming teachers, stoked after 20 first graders died  in an elementary school shooting in Newtown, Conn., in December. Shortly afterward, the National Rifle Association proposed a plan for armed security officers in every school, and legislation to allow school personnel to carry guns was introduced in about two dozen states. All those measures had stalled until now.
Several other states already have provisions in their laws — or no legal restrictions — that make it possible for teachers to possess guns in the classroom. In fact, a handful of school districts nationwide do have teachers who carry firearms. But South Dakota is the only known state with a statute that specifically authorizes teachers to possess a firearm in a K-12 school, according to Lauren Heintz, a research analyst at the National Conference of State Legislatures.
Representative Scott Craig, a freshman Republican in the South Dakota House who sponsored the bill, said he hoped the measure would shift the country’s discourse on school safety.