President Obama praised what he called a "comprehensive long-term deal" that will prevent Iran from getting a nuclear weapon and promised to veto any bill Congress sends him that would prevent the implementation of that deal.
At the White House Tuesday morning, shortly after negotiators in Vienna announced the agreement, the president said that the deal "meets every single one of the bottom lines we talked about this spring," and that it meant that Iran will not develop a nuclear weapon, will not produce the weapons-grade plutonium needed for a bomb, will reduce its centrifuges and get rid of 98 percent of its stockpile of enriched uranium.
"This deal is not built on trust. It is built on verification," he said, speaking in the East Room with Vice President Joe Biden standing by his side. Some of the transparency measures "will be in place for 25 years," and the International Atomic Energy Agency (IAEA) "will have access it needs to past nuclear research."
He mentioned the relief that Iran will receive from sanctions after it completes key steps, and, the president said, all of the measures would be contained in a new U.N. resolution. If Iran violates the deal, "the sanctions will snap back" into place.
The president also said that Congress would be able to review the details of the deal and warned them to consider the alternative to negotiating with Iran.
"The world would not support an effort to permanently sanction Iran into submission," he said, suggesting that Iran would be able to continue working on its nuclear program unmonitored by international inspectors.
He said that he welcomed scrutiny of the deal and the agreement but warned, "I will veto any legislation that prevents the successful implementation of this deal."
"This is not the time for politics or posturing," he said.
After 18 days of intense negotiations, the U.S. and five other world powers unveiled the agreement to freeze Iran's nuclear program for the next decade in exchange for gradual sanctions relief that rolls out as Iran complies with a multi-step process.
"What we are announcing today is not only a deal, but it is a good deal," Federica Mogherini, the high representative of the EU for Foreign Affairs and Security Policy said in Vienna.
Iranian Foreign Minister Javad Zarif stood smiling at the microphones in Vienna as he read in Persian the same statement as Mogherini.
The accord will keep Iran from producing enough material for a nuclear weapon for at least 10 years and impose new provisions for inspections of Iranian facilities, including military sites. And it marks a dramatic break from decades of animosity between the United States and Iran, countries that alternatively call each other the "leading state sponsor of terrorism" and the "the Great Satan."
Mogherini said the deal ensured that Iran's nuclear program would "exclusively be peaceful," and that the agreement marked "a shift" in the Iranians' approach to its atomic work.
The economic and financial sanctions -- including a U.S. and European Union oil embargo -- will be lifted as Iran complies with the terms of the deal and as U.N. weapons inspectors verify their compliance.
The essentials of the deal, including the removal of two thirds of Iran's uranium enriching centrifuges -- reducing their number from approximately 19,000 to 6,000 -- the destruction of its stockpile of already-enriched uranium, and other elements, remain the same as what was in the previously-announced framework agreed in Lausanne, Switzerland in April.
Iran will remain locked out of the U.S. financial system, and an existing U.S. ban on arms sales will continue. A separate U.N. ban on arms sales will be peeled back over time as Iran verifiably complies with the terms of the agreement.