protect every government build public venue arm guard school protect arm teachers texas sheriff shock msnbc host discuss prepare local teachers arm classroom common sense solution betcha sheriff paul cairney argyle texas describe process staff members carry firearms school district sheriff say staff school choose carry firearm go intense round interview train allow carry campus msnbc host flabbergast practice ask sheriff concern safety students school firearms around.sheriff cairney time nothing process become school marshall become school marshal employees must undergo extensive active shooter firearms train state must also undergo mental health evaluation receive school marshal designation texas commission law enforcement must renew license every two years undergo train evaluation outside campuses keene argyle sign warn visitors staff members arm prepare protect children msnbc anchor flabbergast texas teachers protect students video