united states are manufactured by manufacturers who have licenses. traceability is very important. after a gun is manufactured a serial number is placed on the gun. moreover, after guns are sold, they're sold to owners who have to go through a detailed and rigorous background investigation. allowing 3d guns to be manufactured basically obviates all of those requirements. we live in a situation where guns are not traceable, they're not subject to background checks for the owners and most importantly perhaps these guns, because they would be made out of plastic, won't be detectable by common means of detecting guns. guns in schools, guns in government buildings, guns in airports. >> the reality, though, as the nra, the national rifle association, argues is that this would join a -- basically a pile