> The US has veto power in the UN.

Strictly speaking, the US has veto power in the UN Security Council, which usually has primary responsibility for binding actions on matters of international peace and security, including, inter alia, taking binding action in response to threats to the same such as by grave breaches of international law by a nation-state.

However, its worth noting that -- at US urging in the context of the Korean War -- the UN established a mechanism (under the "Uniting for Peace" resolution [0]) by which the General Assembly can step in when the Security Council is unable to act because of deadlock among the veto powers.

[0] http://en.wikipedia.org/wiki/United_Nations_General_Assembly...