"The treaty will require countries that ratify it to establish national regulations to control the transfer of conventional arms and components and to regulate arms brokers,
it will not control the domestic use of weapons in any country.
It prohibits the transfer of conventional weapons if they violate arms embargoes or if they promote acts of genocide, crimes against humanity or war crimes, and if they could be used in attacks on civilians or civilian buildings such as schools and hospitals."
The Constitution and Bill of Rights takes precedence over any International Treaty.
http://www.snopes.com/politics/guns/untreaty.asp