It is worth noting that the Constitution does not DENY cities the authority to regulate firearms or other weapons---only the FEDERAL GOVERNMENT. This was what was known as "states' rights" or "local control." Colonies long had regulations against carrying firearms in church, for example, and the issue that set off the "gunfight at the O.K. Corrall" was that to control the carnage in Tombstone, the Earps required all firearms be checked at the sheriff's office while in town.
The Constitutional issue is not whether people can carry weapons they choose any where, any time, but WHO makes the laws. Emerson essentially upheld this by saying that CONGRESS CANNOT, but that locals (such as Wash. D.C. CAN). Therefore, if you want "concealed carry laws" in Washington, move there and change the law.