I just watched President Abbas' speech at the UN and was very much impressed. He was able to say what needed to be said without the completely forgivable tone of revenge that their position justifies.
There was a lot of support for him in the assembly, so if the USA are going to block this they can just fuck off again. If Palestine were a state they would be able to push for the arrests of the Israeli war criminals who are currently protected by the USA, and that's probably one large factor in the USA saying they won't support the move. After all - if these criminals were charged, the whole story would come out and show in black and white that the USA is a defender and funder of terrorists.
