From The New York Times:

By the end of February, the students at Manatee School for the Arts in Palmetto, Fla., will see two combat veterans in body armor roaming the grounds, each carrying a 9-millimeter Glock handgun and a semiautomatic rifle with a 17-inch barrel.
If an armed intruder were to enter the campus, “we’re not looking for a fair fight,” Bill Jones, the principal, said in an interview. “We’re looking at an overwhelming advantage.”