President Obama Answers Questions on Iran nuclear Deal - Press Conference July 15, 2015

 "I expect the debate to be robust, and that's how it should be," Obama said, imploring lawmakers who are skeptical of the deal to "remember the alternative."

Under the deal announced Tuesday, Iran's nuclear program will be scaled back and closely monitored as the U.S. and world powers seek to cut off Iran's ability to develop a nuclear weapon. In exchange, Iran will see biting economic sanctions eventually lifted, freeing up billions of dollars in oil revenue and frozen assets.

Obama, taking questions from reporters in the East Room, said that in the absence of a deal, the international economic sanctions that brought Iran to the negotiating table will unravel, and the world community will be unable to put the sanctions regime together.

"Without a deal, we risk even more war in the Middle East, and other countries in the Middle East would feel compelled to develop their own nuclear weapons," Obama said, adding that such a chain of events would risk a nuclear arms race "in the most dangerous region in the world."