Obama had sold out the US and singed away US rights to the UN. Even though the Paris Accord finalization a couple years ago was a no go and Trump prevented the US from going forward. The big issue Trump got us out of is the commitment to Fund obama's commitment over the next decade, which I think was in the trillions.  But it doesn't undo what obama already committed to in the 100's of millions which Trump is trying to undo. Fortunately for us obama thought hillary was going to win otherwise there would have been more legal ties that prevented the US from pulling out. Plus it would have been harder to pass what he did if it signed away all US rights to the UN.