Charles Dharapak / AP PhotoPhotos from the G-20 and U.N.When he addresses the U.N. Security Council Thursday, the president will repeat the shocking proposal John Kennedy made a half-century ago: Get rid of nuclear weapons—forever.09.22.09 1:33 PM ETCharles Dharapak / AP PhotoCharles Dharapak / AP PhotoPresident Obama and first lady Michelle Obama welcome France's President Nicolas Sarkozy and his wife Carla Bruni as they arrive for the G-20 summit dinner in Pittsburgh, Thursday, Sept. 24, 2009.Philippe Wojazer, AFP / Getty ImagesPresident Obama and first lady Michelle greet Russia's President Dmitry Medvedev and wife Svetlana Medvedeva as they arrive at the Phipps Conservatory for an opening reception and working dinner for heads of delegation at the Pittsburgh G20 Summit in Pittsburgh.Chris Wattie / ReutersCanada's Prime Minister Stephen Harper and his wife Laureen greet President Obama and first lady Michelle Obama as they arrive at the Phipps Conservatory for an opening reception and working dinner for heads of delegation at the G20 Summit in Pittsburgh, Pennsylvania September 24, 2009. Carolyn Kaste / AP PhotoGerman Chancellor Angela Merkel is greeted upon her arrival at Pittsburgh International Airport in Coraopolis, Pa., Thursday, Sept. 24, 2009.Scott Olson / Getty ImagesSilvio Berlusconi, Prime Minister of Italy, arrives for the G-20 Pittsburgh Summit at the Pittsburgh International Airport September 24, 2009 in Coraopolis, Pennsylvania. Kevin Lamarque / ReutersPresident Obama and first lady Michelle Obama walk towards Air Force One as they depart New York for Pittsburgh to attend the G20 Summit September 24, 2009. Carolyn Kaster / AP PhotoChinese President Hu Jintao is greeted on the tarmac as he arrives at Pittsburgh International Airport in Coraopolis, Pa., Thursday, Sept. 24, 2009.Carolyn Kaster / AP PhotoRussia's President Dmitry Medvedev gets into his waiting car on the tarmac at Pittsburgh International Airport in Coraopolis, Pa., Thursday, Sept. 24, 2009. John Moore / Getty ImagesU.S. Treasury Secretary Timothy Geitner (L) and Japan's Finance Minister Hirohisa Fujii sit for bilateral talks at the G-20 Summit on September 24, 2009 in Pittsburgh, Pennsylvania. The meeting was their first since Fujii became finance minister as part of the new Democratic Party of Japan cabinet. Richard Drew / AP PhotoUproar over AhmadinejadMahmoud Ahmadinejad, president of Iran, waves following his address to the United Nations General Assembly on Wednesday night. The U.S., Canadian, French, and other Western delegations walked out of the speech, protesting his remarks about Israel.Henny Ray Abrams / AP PhotoObama, Ban Do LunchPresident Obama, right, and United Nations Secretary-General Ban Ki-Moon show each other to their seats at a luncheon during the United Nations General Assembly on Wednesday.Seth Wenig / AP PhotoQaddafi Arrives at the SummitLibyan leader Muammar Qaddafi arrives at the 64th session of the General Assembly at United Nations headquarters, Wednesday, Sept. 23, 2009. Charles Dharapak / AP Photo A Rare Trilateral MeetingPresident Obama sits with Israeli Prime Minister Benjamin Netanyahu, left, and Palestinian President Mahmoud Abbas, right, as they begin a trilateral meeting on the sidelines of the United Nations General Assembly in New York on Tuesday.Seth Wenig / AP Photo Focus on the ClimateFrench President Nicolas Sarkozy speaks at the summit on climate change at the United Nations on Tuesday. Rick Gershon / Getty ImagesA Special Mideast EnvoyFormer British Prime Minister—and now special envoy of the Middle East Quartet—Tony Blair meets members of the press after they were briefed on the work of the Ad Hoc Liaison Committee at the United Nations on Tuesday.John Angelillo, Pool / Getty ImagesSpotlight on ChinaPresident Obama listens to President Hu Jintao of China speak at a bilateral meeting at the Waldorf Astoria Hotel on September 22, 2009 in New York City. The two leaders were meeting on the sidelines of the UN climate change summit and the 64th session of the United Nations General Assembly. Frank Franklin II / AP Photo Hollywood Lobbies for the EnvironmentActor Djimon Hounsou speaks at the summit on climate change at the United Nations on Tuesday. Charles Dharapak / AP Phto Obama on the ClimatePresident Obama addresses the United Nations climate change summit on Tuesday.Rick Gershon / Getty ImagesEye on the U.N.President Obama makes remarks at the summit on climate change.