If the PA declare a state on 67 greenline it is inline with Saudi peace plan and would put US in a hard position, its goal seem to be very close to that. If the US sides with Israel on veto, it will push the Muslims away from US, while this is good for Israel it could harm the US in many ways. China could become the big winner in this if they play their cards right, with 3nd world countries key to US exports grown and US unemployment. Most American don't understand this and only see Muslims at the current enemy and Israel as a friend but the US needs Muslim support long term more than Israel's. In WWII Germany and Japan were seen as the enemy only to help build the US economy later.
Police arrest 18-year-old Palestinian suspected in Old City stabbing (Haaretz)
from the article: Palestinians under world pressure not to declare state unilaterally