World Leaders Reach Tentative Deal With Iran -- Now They Have To Sell It

WASHINGTON -- When President Barack Obama made the campaign promise of rapprochement with Iran, his opponents attacked him as naive. On Thursday, more than six years after Obama took office and spoke to Iranians about hopes for better relations, his vision bore tangible results -- though not enough to quiet the critics.

"Today the United States, together with our allies and partners, has reached a historic understanding with Iran which, if fully implemented, will prevent it from obtaining a nuclear weapon," Obama said during remarks in the Rose Garden. "I am convinced that if this framework leads to a final comprehensive deal, it will make our country, our allies and our world safer."

The president emphasized that international negotiators have produced a "good deal" that will "cut off every pathway" that Iran could take to develop a nuclear weapon.

"This deal is not based on trust," he added. "It's based on unprecedented verification."

Speaking moments before the president in a televised news conference from Lausanne, Switzerland, EU Foreign Policy Chief Federica Mogherini and Iranian Foreign Minister Javad Zarif announced the broad details of a comprehensive agreement, aimed at assuring the international community that Irans nuclear program will be restricted to peaceful purposes.

Negotiators from Iran, the U.S. and five partner countries had set a self-imposed deadline of March 31 to agree upon the political framework for a final deal. Some skeptics viewed the deadline -- pushed off twice to allow talks to continue -- as a final chance to pursue a negotiated settlement.

But even though leaders were able to finalize a framework, their work is not yet done. They now have until June 30 to hammer out the final technical details, with some clear tripping points to traverse.

According to Wednesdays announcement, the final nuclear agreement will be effective for at least 10 years, after which point Irans nuclear program will be subject to the same restrictions and inspections as other members of the Nuclear Non-Proliferation Treaty.

Iran has amassed 19,000 centrifuges, 10,000 of which are currently spinning. Under the final deal, the total will be slashed to 6,000, 5,000 of which will enrich uranium at the Natanz nuclear facility. Iran has agreed not to enrich uranium above 3.67 percent for 15 years. The country will be allowed to pursue research and development on more advanced centrifuge technology, which produces uranium at a more efficient rate. It will not, however, build any new enrichment facilities for 15 years.

In exchange for decreasing the number of centrifuges and reducing its stockpile of uranium, Iran will receive sanction relief. Sanctions imposed by the U.S. and European Union will be suspended after the International Atomic Energy Agency has conducted inspections to verify Irans compliance with the deal. For most of the 10-year duration, sanctions could be easily snapped back in the event of violations. Current U.N. Security Council resolutions pertaining to Irans nuclear program will be replaced with a resolution that endorses the final deal. However, sanctions relating to terrorism, human rights abuses and ballistic missiles will remain in place.

Read the White House fact sheet on the parameters of the deal here .

It remains unclear how frequently those inspections by the IAEA will take place, and how much Iran will be required to reveal to international inspectors about any possible past military dimensions of its nuclear program.

The final technical details arent the only variables still to be addressed. Domestically, the president must now sell this deal to a skeptical Congress, and some members have publicly warned Iran that they will seek to undo the deal after the current administration leaves office. Speaking shortly after the contours of the deal were announced, Obama urged the international community and lawmakers in his own country to not let such a historic diplomatic opportunity succumb to political pressures.

"If Congress kills this deal, not based on expert analysis and without offering any reasonable alternative, then it's the United States that will be blamed for the failure of diplomacy," Obama said. "International unity will collapse, and the path to conflict will widen."

Whether Congress heeds his advice is anyones guess. Lawmakers are currently away from Washington on recess. But before they left, momentum had started to grow for legislation limiting the president's flexibility. Obama said Thursday that he planned to call House and Senate leaders later in the day.

One bill, introduced by Sen. Bob Corker (R-Tenn.) would prohibit the implementation of any deal for 60 days, at which point Congress can decide to vote for or against the deal, or do nothing. The bill would prohibit the president from temporarily waiving sanctions against Iran during this period. The Corker bill, which tentatively needs the support of only three more Democrats to secure the 67 votes needed to overturn Obamas promised veto, is scheduled for markup in the Senate Foreign Relations Committee on April 14, the day after the Senate returns from recess.

Corker said Thursday he wanted to wait to see the specifics of the deal before weighing in, but warned that people must "remain clear-eyed" about Irans resistance to concessions. He also emphasized the importance of Congress being able to weigh in on any final deal.

"I am confident of a strong vote on the Iran Nuclear Agreement Review Act when the Senate Foreign Relations Committee takes it up on April 14," he said.

An alternative bill, led by Sens. Mark-Kirk (R-Ill.) and Bob Menendez (D-N.J.) would impose additional sanctions against Iran if negotiators fail to reach a final agreement by June 30. While the Kirk-Menendez bill technically has no effect until after the June 30 deadline, Obama has warned that the threat of additional punishment against Iran could endanger the entire negotiating process.

Complicating matters is the fact that Menendez, one of the primary Democratic opponents of the deal, is embroiled in his own political crisis. The New Jersey Democrat was indicted by the Department of Justice on Wednesday on corruption charges. He has temporarily stepped down from his post as ranking member of the Senate Foreign Relations Committee, replaced by Sen. Ben Cardin (D-Md.). While Cardin is no dove on Iran, he notably has not signed on to the Corker bill or the Kirk-Menendez alternative.

Sam Stein, Jennifer Bendery and Jesse Rifkin contributed reporting.