Why didn't the US veto?

One of the week's most interesting developments was beyond any doubt the decision the United Nations Security Council took against Israel. Surprisingly, the U.S. President Barack Obama administration adopted an attitude contrary to the U.S.'s traditional politics against Israel.The U.S. abstained from voting in the U.N. Security Council on the draft resolution declaring – also according to international law – all Jewish settlements on Palestinian lands, officially occupied by Israel, as illegal,