From the story "Obama faces widespread backlash after abstaining from UN Israel vote" here:
On Friday, the Security Council voted 14-0 on a resolution condemning Israeli settlements in Palestinian territory as a “flagrant violation” of international law that have “"no legal validity." It demands a halt to "all Israeli settlement activities," saying this "is essential for salvaging the two-state solution."
The United States has veto power in the Security Council and has used it for similar resolutions in the past. The Obama administration’s decision to abstain represents a break from the longstanding U.S. policy of shielding Israel from U.N. reproaches.