The failure of six world powers to complete a nuclear deal with Iran by Monday's deadline sets up a political battle between Congress, where lawmakers are calling for tougher sanctions, and the White House, which fears such a move would drive Tehran away from the negotiating table.
Despite a week of almost nonstop high-level meetings in the Austrian capital, diplomats acknowledged they had failed to resolve core issues in the negotiations and announced that they would give themselves seven more months to reach an agreement.
But the impasse strengthened the arguments of critics who contend that if Iran wasn't willing to compromise over the last year of talks, it would be unlikely to do so later.
Several lawmakers on Monday voiced skepticism over the halting diplomatic effort.
"If Iran hasn't been able to make difficult choices over the past year, there is little reason to think the supreme leader will see it differently over the next few months," said Rep. Ed Royce (R-Fullerton), chairman of the House Foreign Affairs Committee. "This seven-month extension should be used to tighten the economic vise on Iran … to force the concessions Iran has been resisting."
Sen. Mark Kirk (R-Ill.), co-sponsor of a bill that would have tightened sanctions on Iran if the parties failed to reach agreement by Monday, said the latest extension would allow the Islamic Republic to continue to benefit financially from the partial sanctions relief provided under a current interim agreement.
"Now more than ever, it's critical that Congress enacts sanctions that give Iran's mullahs no choice but to dismantle their illicit nuclear program and allow the International Atomic Energy Agency full and unfettered access to assure the international community's security," said Kirk, whose bill was co-sponsored by Sen. Robert Menendez (D-N.J.), who chairs the Senate Foreign Relations Committee.
Amid White House lobbying, Senate Majority Leader Harry Reid (D-Nev.) prevented their bill from coming to a vote. But Obama will no longer be able to count on that after Republicans take control of the Senate in January.
Pressure is also likely to grow on Iranian President Hassan Rouhani, who won office in 2013 by promising that a deal would boost Iran's economy. Conservative critics in Iran are questioning whether talks with the West are worthwhile.
The seven countries have been seeking a deal that would ease tough international sanctions on Iran if it agreed to restrictions aimed at preventing it from developing a nuclear weapons capability. The world powers — the United States, France, Britain, Germany, Russia and China — have made progress on a number of disputed areas, diplomats say, but remain divided on the key issues of how much nuclear infrastructure Iran could retain and how quickly sanctions would be lifted.
The deal they have been seeking would help resolve one of Western leaders' most urgent security challenges and could open the way to a new relationship between Iran and the United States after more than three decades of enmity.
The diplomats, who will meet again in mid-December, set two new deadlines: March 1 for a political agreement that will lay down the broad terms of a compromise and July 1 for final agreement on all the details.
The March 1 deadline was set with expectations that it would probably take the new Congress more than five weeks to put in place a new round of tough sanctions or other legislation that could threaten the deal-making. If the world powers nail down the broad outlines of a deal by March, they will probably be in a strong enough position to hold off congressional attacks until July, analysts said.
Administration officials argue that a few more months of delay won't make much difference, and that the U.S. is better off with a continuation of the temporary nuclear deal signed last November. That so-called Joint Plan of Action requires Iran to stop some of its most worrisome nuclear activities in exchange for limited sanctions relief.
Administration officials refused to discuss the details of the negotiations for fear of drawing more public criticism. But that silence makes it harder to convince critics that they are close to the nuclear deal Western diplomats have been seeking for 11 years.
Secretary of State John F. Kerry told reporters Monday that the talks yielded progress "on some of the most challenging elements," including some "new ideas" that surfaced over the last week. But he said he wouldn't release details because it would enable critics to distort the information and attack the process.
"This should not be worked out publicly," he said.
Cliff Kupchan, chairman of the Eurasia Group risk consulting firm, wrote in an analysis Monday that Congress "now emerges as the key player — new sanctions legislation looms which could disrupt or destroy diplomacy."
Analysts predict that both critics and supporters of the administration are going to mobilize over the next few weeks to try to shape American public opinion about the faltering diplomacy.
The extension will give Iran an additional $5 billion in sanctions relief, following the terms set in last year's interim agreement. That economic boost may provide Congress another incentive to add new sanctions.
There had been reports from Western officials that diplomacy was making headway in recent days. By Monday, however, progress halted, officials said, and it remains unclear whether Iran's supreme leader, Ayatollah Ali Khamenei, is willing to make the compromises needed for a deal.
Advocates for diplomacy, including top U.S. officials, had warned that the chances of a successful agreement would diminish if a deal wasn't finalized by Monday's deadline, partly because Rouhani and Obama have grown politically weaker over the last year.
Philip Gordon, senior Middle East advisor at the National Security Council, said this month that failure to do a deal now "drastically reduces" the chance of achieving one.
Rouhani, in a TV address Monday, promised that the "Iranian nation will be the final winner of the negotiations." He signaled that negotiators would stick with Khamenei's demands that Iran be allowed to maintain its full nuclear program.
"We have not compromised and we will not compromise our nuclear rights," he said.
Although reaction in Iran was mixed, some voices raised a familiar criticism that Rouhani had erred in even trying to negotiate with the West.
"There is no use for negotiations with the West," said Hoshang Tale, a conservative former member of parliament. By agreeing to negotiate, "President Rouhani has accepted the violation of our sovereignty," Tale said.