Sometimes a defeat is as good as a victory. A veto here will destroy the US credibility as a fair broker of peace, will show that Israel/US are not ready for serious peace talks and when Abu Mazen turns to a different approach he will have the world 100% behind him. It's basic diplomacy.
Aden hotel used by Yemen goverment hit by grenade (Reuters)
from the article: Palestinian FM: Eight UN Security Council members support statehood bid