It looks like Webb handed the bag off to his staffer because he was boarding a flight. The question of who is the idiot will therefore hinge on one piece of information: did the staffer knew there was a firearm and two extra loaded magazines in the bag? If so, the staffer is the idiot. If not, Jim Webb is the idiot.
There’s also the distinct possibility that both are idiots.
There is also the possibility that they are both “special” and we are not.