President Obama says Iran's "nuclear breakout" time will be extended from the current two or three months to at least a year under the nuclear agreement. But he acknowledges that some restrictions will fall away after 15 years and the breakout time would again shrink. Morgan Walker/NPR hide caption

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President Obama spoke with Morning Edition host Steve Inskeep at the White House last week. Nick Michael/NPR hide caption

itoggle caption Nick Michael/NPR

A coal scraper machine works on a pile of coal at American Electric Power's Mountaineer coal power plant in 2009 in New Haven, W.Va. The state, in which coal mining is a major industry, is one party planning to sue the Environmental Protection Agency regarding new power plant regulations announced Monday. Saul Loeb/AFP/Getty Images hide caption

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The Japanese supercomputer K, pictured in June 2012 at the RIKEN Advanced Institute for Computational Science in Kobe, western Japan. The K computer is currently ranked No. 3 on a list of the 500 fastest supercomputers. Kyodo/Landov hide caption

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President Obama and his delegation stand Monday during a welcome ceremony with Ethiopia's Prime Minister Hailemariam Desalegn at the National Palace in Addis Ababa, Ethiopia. Tiksa Negeri /Reuters /Landov hide caption

itoggle caption Tiksa Negeri /Reuters /Landov

A supporter waves a Cuban flag in front of the country's embassy after it reopened for the first time in 54 years on July 20 in Washington, D.C. The embassy was closed in 1961 when U.S. President Dwight Eisenhower severed diplomatic ties with the island nation after Fidel Castro took power in a communist revolution. Mark Wilson/Getty Images hide caption

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Workers finish installing a billboard showing Kenya's President Uhuru Kenyatta and President Barack Obama in downtown Nairobi a day before Obama's visit. Ben Curtis/AP hide caption

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A man in Nairobi, Kenya, stands in front of a mural of President Obama, created by the Kenyan graffiti artist Bankslave, ahead of Obama's trip to Kenya and Ethiopia. Ben Curtis/AP hide caption

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Iran's Supreme Leader Ayatollah Ali Khamenei delivers a sermon during morning prayers for the Eid al-Fitr holiday, marking the end of the holy month of Ramadan. He signaled his approval of the nuclear agreement with Western powers but reiterated that Tehran's policy toward the "arrogant" United States would not change. Reuters/Landov hide caption

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President Obama joins comedian Bill Cosby and others to sing "Happy Birthday" to Sen. Edward M. Kennedy, D-Mass., on March 8, 2009, at The John F. Kennedy Center for the Performing Arts in Washington, D.C. Haraz N. Ghanbari/AP hide caption

itoggle caption Haraz N. Ghanbari/AP