Earlier this week a group of 47 Republican senators sent a letter to the Iranian government explaining how the US Congress functions, noting that executive agreements can be overturned by Obama’s successor “with the stroke of a pen.” The letter came as the U.S. and several other nations are engaged in negotiations over Iran’s nuclear program. Today, Iran’s Supreme Leader, Ayatollah Khamenei said the letter raised concerns about the trustworthiness of the US government and was “a sign of the decay of political ethics in the American system.” Richard Haas, president of the Council on Foreign Relations, joins us to discuss how the state of the negotiations and the implications of the letter on US foreign policy. PHOTO: From left, Secretary of State John Kerry, Defense Secretary Ash Carter, and Joint Chief Chairman Gen. Martin Dempsey, testify on Capitol Hill in Washington, Wednesday, March 11, 2015, before the Senate Foreign Relation Committee.(AP Photo/Pablo Martinez Monsivais)