It gives commanders broad authority to limit this for their installations
The Joint Base San Antonio Commander has shut down any non-duty carry of any weapons
Other around the nation have done the same
So bases are ‘may issue states’? OK, time to change them to shall issue.
At a time when any commanding officer can be removed, if anyone under his command has an "incident" involving a gun and the CO had authorized carrying firearms, then there may be some reluctance on the part of CO's to authorize carry.
This would change instantaneously if, at the next instance of a terror incident on a base where carry is not authorized, Trump chose to cashier the commander for placing his men at risk.