Presumably the US voted FOR it too, instead of vetoing it.
You can thank Obama. He is going to get your guns one way or another.
“The U.S., however, indicated last week that it would vote for the treaty despite opposition from the pro-gun group, Reuters reported.
The National Rifle Association has portrayed the draft treaty as a threat to gun ownership rights enshrined in the U.S. Constitution and has lobbied to defeat the proposal at the U.N. The NRA last week praised the Senate’s passage of an amendment to the Democratic budget proposal that would prevent the U.S. from entering into the treaty.”
UN adopts pact to regulate multibillion-dollar global arms trade
Veto power can only be exercised in the Security Council, not the General Assembly which is a just who has the most votes for what.