FILE - An unidentified aide hands the formal agreement between Iran and the United States, to a smiling Warren Christopher, then U.S. Deputy Secretary of State, prior to a signing ceremony at the Algerian Foreign Ministry in Algiers, in this Monday, Jan. 19, 1981 file photo. The US and Iran agreed during the night, on terms to free the 52 American hostages held in Iran. Christopher, who led the negotiating team, greeted the hostages as they the aircraft. Christopher died from complications of kidney and bladder cancer at his home in Los Angeles Friday March 18, 2011. He was 85. (AP Photo)