TheTrumpadministration ran into immediate opposition after its top diplomat officially informed theUnited Nationsit is demanding the restoration of all U.N.sanctions on Iran, with allies and opponents declaring the U.S. action illegal and doomed to failure.U.S. Secretary of State Mike Pompeo insisted Thursday that the United States has the legal right to “snap back” U.N. sanctions even though President Donald Trump pulled out of the 2015 nuclear deal between Iran and six major powers that was endorsed by the U.N. Security Council.Russia and China, along with European allies Britain, France and…