President Obama speaks beside Russian President Dmitry Medvedev after signing New START documents in 2010. Now five years old, that treaty has taken on renewed relevance in light of the framework nuclear deal between the U.S. and Iran. Joe Klamar/AFP/Getty Images hide caption

itoggle caption Joe Klamar/AFP/Getty Images

Sen. Bob Corker, R-Tenn., chairman of the Senate Foreign Relations Committee, will shepherd bills on Congress' reaction to the Iran framework deal struck by President Obama. J. Scott Applewhite/AP hide caption

itoggle caption J. Scott Applewhite/AP

Fighters from the Free Syrian Army and the Kurdish People's Protection Units battle ISIS militants in Kobani, Syria, in November. U.S. officials haven't said whether they will defend the forces if they are attacked by Bashar al-Assad. Jake Simkin/AP hide caption

itoggle caption Jake Simkin/AP