The Resolution states  "The continued Israeli settlement of the West Bank had no legal validity, constituting a flagrant violation under international law and a major obstacle to the vision of two States living side-by-side in peace and security."

Settlements in the West Bank violate the Fourth Geneva Convention, which states: "The occupying Power shall not deport or transfer parts of its own civilian population into the territory it occupies." 

Obama is on pretty solid ground here so he takes the final shot on the way out.