>>The US does NOT have to follow ANY UN mandates.

The General Assembly
Decisions of the Assembly have no legally binding force for Governments.
This is well recognised. (They do carry the weight of world opinion though).

The Security Council
The Security Council has the power to make mandatory resolutions
which are binding on Governments. It is rare that these occur because
of the veto power enjoyed by the five permanent members. The U.S. has
traditionally clubbed anything it didn't like with its veto power
(including resolutions critical of Israel).
Security Council Resolutions which the US doesn't like get killed procedurally.
They don't have to refuse to follow mandatory resolutions. They can kill anything they want to with the veto before it comes into existence. And they do.

Not saying this is how it should be. Just how it is.