Analysis: Obama begins hard Iran sell to sceptical Congress

The tough negotiations leading to a nuclear deal with Iran may have concluded in Vienna, but the hard work on selling the agreement to sceptical Republicans and Democrats is only beginning in Washington. The US Congress has 60 days to review the deal, a concession president Barack Obama ceded to lawmakers on Capitol Hill to smooth the path to his legacy-defining agreement.

Obama is unable to waive economic sanctions during that time so, given that the agreement on Tehran curbing its nuclear programme rests on sanctions being lifted, implementation of the agreement is on ice while Congress considers it.

Against the backdrop of a full-blooded presidential campaign with a crowded field of 15 Republican candidates (and rising), expect plenty of heated congressional committee hearings, angry denunciations of the agreement and inflammatory statements from Mr Obama’s opponents who believe the Democratic president has again conceded too much to a long-time adversary and threatened alliances overseas.

Mr Obama spent less than half of his 14-minute address describing the nuts and bolts of the deal and the remainder trying to sell the agreement. It is notable that he thanked Democrats and Republicans for passing sanctions “that have proven so effective” before thanking the international negotiators from the “P5+1” countries that brokered the agreement or even his own negotiators in Vienna.

Obama stressed that there was no alternative to the deal, remarks aimed at his congressional doubters and America's allies, Israel and the Sunni Arab states who fear the deal will only embolden Iran.

Most Republicans and many Democrats have been uneasy for months, particularly since the initial framework agreement was unveiled in April, that the US had shifted position, from pushing Iran to dismantling their nuclear programme to managing it.

Even if Congress votes no, the president has said he would block it with a veto. To override that veto, two-thirds of Congress need to vote against him. In the House of Representatives, Republicans hold 244 seats and require 290 votes to overcome a veto, a steep climb. In the Senate, if all 54 Republicans vote against it, they would need at least 13 Democrats to reach the magic number of 67 to derail the deal.

The rebellion required within Obama's own party to kill off one of their president's landmark achievements seems unlikely, and neither is it a foregone conclusion that all Senate Republicans will vote against it. A cautious endorsement from 2016 Democratic frontrunner Hillary Clinton, who as president would have to police Obama's agreement, may help sway wavering Democrats.

On the other side, the rhetoric from the most vocal Republican critics on the negotiations was unsurprisingly belligerent. Foreign policy hawk Senator Lindsey Graham, a Republican presidential candidate, called the deal "the most dangerous, irresponsible step I've ever seen in the history of watching the Mideast". He told Obama to "get out your pen", pointing to the prospect of a disapproving Congress and the president signing a veto.

Several key figures will play a pivotal role. Chuck Schumer, the third-highest ranking Democrat in the senate, has consistently supported legislation to impose more sanctions on Iran if there was no deal. A senator from New York, Schumer, along with other Democrats such as Robert Menendez of New Jersey and Kirsten Gillibrand of New York, must answer to large Jewish constituencies who may, like Israeli leader Binyamin Netanyahu, see the deal as a "historic mistake".

Ben Cardin, a Maryland Democrat and the party's highest member of the Senate foreign relations committee, helped to broker the review of the Iran deal between Congress and the White House and may help win over undecided Democrats.

Republicans Bob Corker of Tennessee, chairman of the committee, and Jeff Flake of Arizona, another member, have been less incendiary in their remarks on the Iran talks than others in their party and could prove helpful allies for Obama. Both were among seven Senate Republican who did not sign a letter to Iran's leaders from freshman senator Tom Cotton of Arkansas and 46 other Republican senators in March, telling Tehran that Congress did not intend to honour a deal.

Cotton, a former US war veteran, has suggested that military action against Iran’s nuclear facilities would take just “several days,” a proposition rubbished by some and at odds with Obama’s peaceful approach. Finding agreement on what would be a signature accomplishment of Obama’s presidency will take far longer.