As international negotiators gathered here Saturday for what is supposed to be a final round of nuclear diplomacy with Iran, the hope of achieving a deal hinges on a mystery: What does Iranian supreme leader Ayatollah Ali Khamenei really want?
An agreement limiting Iran's nuclear program would potentially be the most important diplomatic achievement of the decade, and it has seemed increasingly within reach since April 2, when negotiators reached a tentative deal.
But in recent weeks, Khamenei has moved away from understandings his negotiators had appeared to agree on. In particular, he has said he would refuse to allow international inspectors access to sites of suspected nuclear activity, including military bases.
The six world powers seeking the agreement have called scrutiny of Iran's military sites a necessary part of any deal to prevent Iran from cheating on a nuclear accord. Khamenei and other top Iranian officials and lawmakers have repeatedly insisted that they will refuse such access.
Western officials still believe odds favor a deal after almost two years of bargaining. Some believe Khamenei is only seeking advantage ahead of the June 30 negotiating deadline.
But in Washington and European capitals, concern has deepened in recent weeks that Khamenei may truly be unwilling — or perhaps politically unable — to make the concessions needed to seal a fundamental compromise with foreign powers.
"People expected the Iranians to spout off, then simmer down," said Richard Nephew, who was a member of the U.S. negotiating team until earlier this year. "But they haven't; they've dug in deeper."
As Secretary of State John F. Kerry and other diplomats gathered at a former Habsburg palace here over the weekend, they insisted a deal was within reach, even as they conceded questions that seemed resolved in April are again in dispute.
"Everybody would like to see an agreement, but we have to work through some tough issues," Kerry said Saturday before a meeting with Iranian Foreign Minister Mohammad Javad Zarif.
Negotiations were expected to continue past the deadline by at least a few days and could last until mid-July. The final days will probably feature threats, all-nighters and perhaps even some theatrical departures, diplomats said.
Those who see Khamenei's tough statements as a negotiating tactic note that each side nonetheless has compelling strategic reasons to want a deal. The U.S. and the five other world powers involved in the talks — Britain, France, Germany, China and Russia — are hoping to postpone the threat of the Iranian nuclear program for at least 10 to 15 years; Iran desperately needs relief from punishing economic sanctions and seeks to end its status as international pariah.
Yet an agreement would be a huge step for an Iranian elite whose authority and personal wealth has been built on four decades of resistance to the United States. And Khamenei knows that among ordinary Iranians, much of the credit for the deal would not go to him and the hard-liners who back him, but to their more moderate rivals, including Iranian President Hassan Rouhani.
"An elite firestorm" over the issues of inspections and the United Nations' desire to look into Iran's past nuclear weapons research has clearly threatened the supreme leader, wrote Cliff Kupchan, chairman of the Eurasia Group risk-consulting firm, in a report this month.
Since the April 2 tentative agreement, conservatives in parliament, the religious establishment, state media and the Iranian Revolutionary Guard Corps, all key parts of Khamenei's power base, have voiced criticism. There have been mass demonstrations and personal attacks on the negotiators, including during Friday prayers in Tehran.
The idea of inspections on military bases has generated particular controversy, with many in Iran saying the plan offends the country's dignity and treats it in a manner that no other country would allow.
How much Khamenei responds to such pressure remains a matter of intense debate among U.S. and allied officials.
The bargaining that began in September 2013 has allowed U.S. officials insights into the Iranian government they have not had in the 36 years since the Iranian Revolution. They now have regular access to top Iranian officials; U.S. diplomats have a congenial personal relationship with Iran's suave foreign minister, Zarif.
But the 75-year-old Khamenei remains an enigma. Within the U.S. government, opinions differ on the extent to which he is the decider, and on whether he can only struggle to shape a consensus of the most powerful political forces within the Iranian elite.
U.S. analysts see Khamenei as a weaker leader than his predecessor, Ayatollah Ruhollah Khomeini, the founder of the Islamic Republic, who had more charisma and broader public support. Khamenei has struggled to juggle the goals of his hard-line inner circle with public demands for a better economy through an end to sanctions and an increase in foreign investment.
Last July, negotiators thought they had a deal, but Khamenei dashed their hopes just before a deadline by demanding that Iran's nuclear program, instead of shrinking, be allowed to expand many-fold over the course of a deal that he said should last for only seven years. Khamenei's red lines later melted away, as he seemed to accept a sharply constrained uranium-enrichment program and a longer duration for the nuclear deal.
When Khamenei appeared to accept the interim deal in April, some analysts and former U.S. officials said it appeared that the leader was turning out to be a pragmatist, rather than a fire-breathing revolutionary, as he had described himself. Now those judgments are again in doubt, particularly after a nationally televised speech Wednesday in which Khamenei seemed to rule out many of the compromises that Iranian negotiators had accepted.
In the speech, he said Iran must have relief from sanctions at the start of any agreement, not after it had taken verifiable steps to scale back its nuclear program, as previously agreed. He also said Iran wouldn't agree to a decadelong freeze in its uranium enrichment, as stipulated in April.
Khamenei made other provocative statements that appeared aimed at encouraging hard-liners. He claimed that President Obama had secretly offered to recognize Iran as a nuclear state in 2013 and appeared to be boasting that Iran's ability to enrich uranium to 20% put it within easy reach of having material usable in a bomb, noted Ray Takeyh, an Iran specialist at the Council on Foreign Relations.
Khamenei also again ruled out "unconventional" activities by inspectors, including access to military bases and interviews with nuclear scientists.
The supreme leader may have several goals in mind. He may be trying to force a reopening and renegotiation of settled issues, following a pattern seen in past Iranian negotiations. He could be trying to temporarily placate hard-line constituencies at home, with a plan to back off later. Or he could have decided that pressure from the Revolutionary Guard and other conservative institutions has left him no choice but to jettison previous commitments, even if doing so threatens the deal.
Khamenei could pay a huge price for throwing up demands that would sink the deal. Iran could be blamed for a diplomatic collapse, raising the chances that world powers would agree to maintain, or even toughen, the sanctions that are crushing Iran's economy.
But his moves, at the very least, may make it impossible to complete the deal within a period even close to the current deadline. His negotiators now face a daunting task of squaring their past promises with the leader's pronouncements.
For the Obama administration, the effective deadline to complete the deal is around July 5. If the agreement isn't in hand then, the administration probably won't be able to meet a congressional deadline to provide lawmakers the text and all supporting documents by July 10. If the administration misses that deadline, Congress gets an additional month to review the deal, putting a final decision off to mid-September at the earliest.
Nephew, the former negotiator, says he remains optimistic that a deal will be struck. "It's so important, for so many strategic reasons, for both sides," he said. "But it could also fall apart."