President Barack Obama, left, greets Deputy Prime Minister and Minister of the Interior of the Kingdom of Saudi Arabia, Saudi Crown Prince Mohammed bin Nayef bin Abdulaziz Al Saud, center, and Second Deputy Prime Minister and Minister of Defense and Deputy Crown Prince Mohammed bin Salman bin Abdulaziz Al Saud, right, as they arrive at the South Lawn of the White House in Washington, Wednesday, May 13, 2015. Gulf nation leaders gathered in Washington to warn President Barack Obama of the risks of completing a nuclear deal with Iran. Obama will try to convince them of the potential benefits for the region. (AP Photo/Manuel Balce Ceneta)