Niall Ferguson gives about as succinct an explanation for the Palestinian failure at the UN this weekend, as you’re likely to find:
They will get their own state eventually. But not until all the permanent members of the Security Council are convinced the Palestinians will not abuse the privileges of statehood.
The UN was founded on the idea — on the mostly-naive hope, really — of collective security. New nations don’t get to join, predicated on the idea of the destruction of another member.