President Barack Obama defended the historic nuclear deal with Iran as he faced White House reporters Wednesday at a press conference. "It prevents the most serious threat, Iran obtaining a nuclear weapon, which would only make the other problems that Iran may cause even worse. That's why this deal makes our country and the world safer and more secure," the president said. Six world powers, including the United States, reached the deal on Tuesday. It aims to limit Iran's nuclear capability in exchange for lifting punishing economic sanctions. Obama has said the deal eliminates every pathway to an Iranian nuclear weapon. The deal still faces a vote in Congress, although it is unclear whether Republicans and some Democrats who object to the deal will actually be able to override the decision — and Obama threatened Tuesday to veto any attempt to reject the accord.