Rapprochement with Iran – the United States' most unpredictable enemy since the mullahs toppled the Shah more than three decades ago – might eventually emerge as President Barack Obama's most significant foreign-policy achievement.
Ending the enmity, if not quite deserving of the Nobel Peace Prize the President has already pocketed, would avert the risk of a nuclear-weapons race in the region. The pact to expose Tehran's nuclear program to international inspection is only a first step.
But hawks are circling over Capitol Hill and Mr. Obama's bargain with Tehran is imperilled, not just by doubters like Benjamin Netanyahu in Jerusalem and John Baird in Ottawa who claim Iran's leaders can't be trusted, but more importantly by defecting Democrats.
Nearly two dozen Democrat senators have joined Republicans in backing a bill that would slap new sanctions on Iran. Mr. Obama has vowed to veto any new sanctions. But a showdown looms. In a rare show of bipartisanship, the pro-sanctions group is nearing the magic number of 67 – sufficient to provide the veto-overriding two-thirds majority in the 100-seat Senate that could doom the deal under which Tehran has agreed to stop enriching uranium to anywhere close to weapons-grade.
President Obama's domestic problems with his Congressional flank were made worse Tuesday by some internal politicking in Iran.
Iran's President Hassan Rouhani boasted United States had capitulated to Tehran in the deal, saying on Twitter that "world powers surrendered to Iranian nation's will." That may please hard-liners at home but is certain to inflame them in the United States. The White House sought to dampen the impact, saying Mr. Rouhani was playing to a domestic audience. "It doesn't matter what they say. It matters what they do," said Mr. Obama's spokesman Jay Carney.
Fearing Congressional meddling, the White House has lashed out, seeking to portray the sabre-rattling for new sanctions as an unwelcome call for confrontation.
"If certain members of Congress want the United States to take military action, they should be up front with the American people and say so," said Bernadette Meehan, one of Mr. Obama's National Security Council team said as more Democrats backed the sanctions bill.
Unbowed, some top Democrats, including New Jersey's Senator Bob Menendez, a co-sponsor of the sanctions legislation and chair of the powerful Foreign Relations Committee shot back: "This is hardly a march to war." Still he insists that Iran's actions show the "need for additional prospective sanctions is already clear."
The stay-tough on Tehran constituency echoes the view voiced by Canada's pro-Israeli foreign minister. "Iran has not earned the right to have the benefit of the doubt," Mr. Baird after the interim deal was struck.
Mr. Obama is trying to buy time, at least until after his State of the Union address on Jan. 28 when he is expected to defend the deal as a historic first step in refashioning relations with Iran.
"Now is not the time for us to impose new sanctions. … We will be able to monitor and verify whether or not the interim agreement is being followed through on, and if it is not, we'll be in a strong position to respond," said Mr. Obama. "What we want to do is give diplomacy a chance and give peace a chance."
The six-month interim deal gives international inspectors daily access to some of Iran's major nuclear sites. Tehran has agreed to limit enrichment of nuclear materials and begin a drawdown of its stockpile of already-enriched uranium.
In turn, more than $7-billion (U.S.) in sanctions relief will flow to Tehran's coffers, giving the cash-strapped Islamist government some room to rebuild the sanctions-savaged Iranian economy.
The interim deal buys time for a permanent pact to be hammered out between Tehran and the so-called P5+1: the United States, Russia, China, Britain, France and Germany.
"The next phase poses a far greater challenge: negotiating a comprehensive agreement that resolves outstanding concerns about the peaceful nature of Iran's nuclear program," State Secretary John Kerry said.
Ultimately, any deal, no matter how many players and signatories it includes, will re-fashion the relationship between the region's largest non-Arab state and that world's sole remaining superpower. Similarly, should the pact fail, it could trigger a wider conflict in a region already racked by strife.
Backers of the diplomatic process accuse those on Capitol Hill who want to impose tougher sanctions of making war more likely – not less.
"War is the true alternative offered by those here who would interfere or limit these negotiations," said Representative Lloyd Doggett, a Democrat from Texas.
Mr. Obama has invited all Democrat senators to the White House for dinner Wednesday. On the menu will be a plea to let talks with Tehran proceed.