Criminals don't obey laws, you only disarm law abiding citizens.
By definition, criminals do not follow laws, and if someone wished to do harm in an executive office, I doubt that the law would stop them from bringing a firearm there. The only people that this would disarm are law abiding citizens, like myself, who would be unable to defend themselves if a criminal tried to harm us in an executive building. Though is is unconstitutional to infringe on one's right to bear arms at all, you should at least allow for open carry in such areas. Security will be able to see who is armed for their protection and you allow the citizens the ability to defend themselves. Don't make us sitting ducks and protect your citizens by allowing them to defend themselves.