Iran's first fear about its controversial nuclear program has long been that it could provoke a US or Israeli military strike.
And a close second, until now, has been concern in Tehran that Iran could be referred to the United Nations Security Council for violations of the nuclear Non-Proliferation Treaty (NPT).
But even as Western diplomats begin to step up efforts to go after Iran at the UN - canvassing began in Vienna Monday, in the wake of the latest Iran report by the UN's International Atomic Energy Agency (IAEA) - Iran appears to be changing tack.
Tehran is minimizing the risk of Security Council sanction, which in turn is undermining the carrot-and-stick approach used by the EU and Washington in recent years to convince Iran to end all nuclear efforts.
"To a certain extent, [Iranian officials] have lost their fear of the Security Council," says Davoud Hermidas Bavand, a professor of international law at Alameh University in Tehran. "Some even say that Iran should take the issue to the Security Council, against the IAEA," he says, because a technical issue has become "politicized."
Shortly after the hard-liner Mahmoud Ahmadinejad was sworn in as president a month ago, Iran took a long-anticipated step of breaking IAEA seals at its Isfahan plant, ending a unilateral suspension of uranium-conversion activities.
The US says those activities - which the IAEA reports have converted seven tons of raw uranium into gas that can be enriched - are aimed at producing nuclear weapons. Iran denies the charge, saying it needs nuclear power, and that its right to master nuclear fuel technology is enshrined in the NPT.
The suspension was part of an earlier deal between Iran and Britain, France, and Germany, which sought to make it permanent in August by offering modest incentives. Iran rejected the proposal, which included no guarantees from the US of safety or waiving of current sanctions, prompting the Europeans to cancel meetings set for late August.
The confidential report, released Friday, found that 2-1/2 years of "intensive inspections and investigation" have not clarified outstanding issues, and that "Iran's full transparency is indispensable and overdue."
Still, the IAEA reported "good progress" in resolving a string of issues since 2003, and confirmed that traces of weapons-grade uranium found on centrifuge parts - held up by some US officials as evidence of a clandestine bomb effort - originated in Pakistan, as Iran has claimed.
Iran's new nuclear negotiator, Ali Larijani, said IAEA criticism was politically motivated, and that violations were "neither legal or technical."
"The tide of opinion in Tehran seems to have shifted," says Gary Samore, a nonproliferation official during the Clinton administration and vice president of the MacArthur Foundation in Chicago.
"Over the last two years, Iran's policy has been dominated by the desire to avoid referral to the Security Council, and Iran has been prepared to accept limits on its nuclear program in order to achieve that," says Mr. Samore, who is releasing an Iran dossier Tuesday under the auspices of the International Institute of Strategic Studies in London. "It does appear that Iran feels it's in a much stronger position."
High oil prices may give Tehran confidence that the council would not jeopardize the flow of Iran's petroleum into the market, says Samore. Other factors include American preoccupation with Iraq, and the decisive victory of Mr. Ahmadinejad at the polls last June.
Likely allies of Iran on the council include China and Russia, which is building a nuclear-power plant at Bushehr. Over the weekend, Russian officials made clear they saw "no reason" to send Iran to the council. Mr. Larijani is due to arrive in Pakistan Wednesday, after visits to China and India to galvanize non-Western support.
"The belief that [the US and EU] can weaken the will of this great nation with the baton of the Security Council is mistaken logic, and they are only losing their dignity," Larijani told Iranian state TV.
"Gone is the time when they could deny Iran its rights by threatening it," Foreign Ministry spokesman Hamid Reza Asefi, said on Sunday. "It is our legitimate right to have peaceful nuclear technology, and we will not give that up."
Europeans hope for a shift during talks between Ahmadinejad and other world leaders, including Russia, at the UN General Assembly in New York next week. The IAEA board of governors meets on Sept. 19 to consider the case.
"Ahmadinejad, and [Iran] in general, feels less threatened by the possibility of sanctions - they perceive they are stronger, and much more in control," says Hadi Semati, a political scientist from Tehran University, who is currently at the Woodrow Wilson International Center for Scholars in Washington. "Domestically in Iran, it's going to be very hard for anyone to come out and say: 'OK, we're going to get rid of our [nuclear] fuel cycle' to get a few promises. That is political suicide.
"They know the Europeans are terrified to take Iran to the Security Council, because then the question is: 'What next?' '' says Mr. Semati. And "down the line, [they feel] the US is bent on regime change anyway, even if it's not declared policy - so why bother?"
But such conclusions in Tehran are a high-stakes gamble, as is likely to be any Security Council response. Numerous safeguard violations over the past 20 years means that "until Iran restores confidence in its nuclear program, it should accept limits on activities that are dual use, and have military applications," says Samore. "There is a very strong legal case, [but] Council members are going to be very reluctant to impose significant sanctions on Iran."
A tough stance could prompt Iran to relaunch uranium enrichment, kick out inspectors, or - as some hard-liners have demanded - pull Iran out of the NPT.
"I think the council will react very cautiously, very incrementally," adds Samore. "It will take time, but there is no urgency. Iran is still a couple of years from having a nuclear-weapons capability, and there are some pretty significant technical problems."