The UN is capable of using an International Trade Treaty to infringe on the US's Second Amendment rights through the Arms Trade Treaty.(See ATT)
Recently in Australia, politicians revoked the peoples Right to Bear Arms completely, which ENCOURAGES crime, home invasion, murder, armed robbery, etc. Crime has skyrocketed to uncontrollable levels, and their Police Services are unable to handle crime levels.(See Aussie Crime Rates)
We must revive the Second Amendment the way it was originally written in the Constitution: "A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, SHALL NOT BE INFRINGED."
citations:
ATT: http://www.un.org/disarmament/ATT
ACR: http://apo.org.au/research/crime-statistics-20112012