Activists around the world are campaigning for the first ever Arms Trade Treaty.
Arms are a $60bn a year business – with the potential to escalate conflict and contribute to atrocities.
While fruit and bottled water are subject to strict international trade rules, the conventional weapons market is currently open to anyone.
For the first time, the US - the world's largest exporter of weapons - is prepared to sign on to the treaty.
There are concerns though that such a treaty would be hard to implement.
Al Jazeera's Kristen Saloomey reports from New York.