What the idealists think they are doing is cutting off the flow of arms to ethnic militias loyal to political leaders and terrorist groups. In reality, what such a foolish treaty would do is cut off access to firearms by the people who need them to defend themselves against the militias and the terrorists.
A coincidental side effect, which doubtless would be supported by the Obamists and similar useless, anti-constitutional-rights vermin, would be to cut off access to foreign-made or stored firearms for American citizens. This is the sort of thing that the U.S. government is supposed to guard out citizens against; but with the current misadministration in office, I question that they will uphold the oaths they swore when they took office, from Obama on down. They are believers in, and practioners of, relative morality.
The more I read about the machinations of the United Nations, the more I am convinced the United States of America needs to withdraw from the useless, corrupt organization and boot them out of our country. This is merely the latest example of their pushing something that infringes on Americans' civil rights.
