UNITED NATIONS — The U.S. decision to allow the U.N. Security Council to condemn Israeli settlements in the West Bank and east Jerusalem could spur moves toward new terms to end the Israeli-Palestinian conflict. But it also poses dangers for the United Nations with the incoming Trump administration and may harden Israel's attitude toward concessions.

The Obama administration's decision to abstain and allow the U.N.'s most powerful body to approve a long-sought resolution calling Israeli settlements "a flagrant violation under international law" was a sharp rebuke to a longstanding ally and a striking rupture with past U.S. vetoes.

Image: United Nations Vote on Resolution Condemming Israeli SettlementsThe United Nations Security Council votes on Friday. Justin Lane / EPA

U.S. Ambassador Samantha Power said "it is because this resolution reflects the facts on the ground — and is consistent with U.S. policy across Republican and Democratic administrations throughout the history of the state of Israel — that the United States did not veto it."

She cited a 1982 statement by then-President Ronald Reagan that the United States "will not support the use of any additional land for the purpose of settlements" and that "settlement activity is in no way necessary for the security of Israel."

The Security Council vote Friday, however, was anything but routine for Washington, which traditionally vetoes all resolutions related to the decades-old Israeli-Palestinian conflict on grounds that differences must be solved through negotiations. It was the first resolution on the conflict approved during President Barack Obama's nearly eight years in office and shone a spotlight on his icy relationship with Israeli Prime Minister Benjamin Netanyahu.

The U.S. decision to abstain on the 14-0 vote followed months of intensely secret deliberations in Washington, a spate of fresh Israeli settlement announcements that sparked exasperation and anger from American officials, and recent attempts by Israel's government to have parliament legalize thousands of homes built on privately owned Palestinian land....Read more at NBC News