The new wave of international sanctions against Iran will hurt its economy - already suffering from mismanagement and corruption - but not enough to change Tehran's nuclear policy, many analysts say. However, the sanctions should give Barack Obama, the US president, the "political space" at home to attempt engaging with Iran once more, said Sir Richard Dalton, Britain's former ambassador to Tehran and a fellow at Chatham House, a leading British think tank.
That engagement might have a chance of changing Iran's calculations and resolving the tangled nuclear dispute - although expectations among many foreign policy experts such as Mr Dalton are not high. A resumption of long-stalled talks is expected next month or in October between world powers and Tehran on Iran's nuclear programme. But yesterday, in a further demonstration of Iranian defiance, the country's vice president and atomic chief, Ali Akbar Salehi, announced that the construction of a new uranium enrichment site, Iran's third, would begin next March.
Mr Obama has been under constant pressure to act tough on Iran from hawkish pundits in Washington, among them many who clamoured loudest for invading Iraq. But having secured tougher sanctions against Iran than his predecessor, George W Bush, ever managed, Mr Obama can now argue that the US will enter any new talks with Iran from a position of strength. At a briefing with senior US correspondents earlier this month, Mr Obama said there were "rumblings" from Tehran that it was feeling the pain from sanctions. At the same time, he put the issue of talks with Iran back on the table, saying he was leaving the "pathway" open for a peaceful resolution of the nuclear issue.
Mr Obama's aides believe that technical problems with Iran's nuclear programme have bought at least a year for sanctions and diplomacy to work, said a New York Times editorial after the White House briefing. But his dual-track strategy has failed to silence Washington's hawks. "The drumbeat for war from neo-conservative pundits and from Israel has only increased" since the "crippling, indiscriminate" new sanctions were imposed, said Trita Parsi, an Iran expert at the Washington-based Woodrow Wilson International Center for Scholars.
"The war drums may not necessarily be to make Obama bomb Iran, but to portray him as weak to hurt him in the upcoming [congressional] elections [in November]," Mr Parsi added in a telephone interview. "If successful, a new domestic political reality will likely emerge that makes a military campaign more probable." Mr Dalton, however, said such pundits could "fulminate as much as they want but my reading of the American military is that war against Iran is the very, very last thing they want".
Mr Obama's main military adviser made this clear at the beginning of the month. Admiral Mike Mullen, chairman of the US joint chiefs of staff, acknowledged the US does have a plan to attack Iran if needed to stop Tehran acquiring nuclear weapons. But in an interview with NBC Television, he left little doubt this was an option of last resort. Adm Mullen said he would be "extremely concerned" about the prospect of a military engagement that could have unintended and unpredictable consequences in "an incredibly unstable part of the world".
Mr Dalton said the pressure of sanctions was of less importance to Tehran than the nature of any new offer the international community may make if nuclear talks resume. The key issue for Iran, which insists its nuclear programme is for civilian purposes only, is that it can continue enriching uranium on its own territory under international safeguards. At his White House briefing, Mr Obama left open the possibility that the US would accept a deal that allows Iran to maintain its civilian nuclear programme, so long as Tehran provides "confidence-building measures" to verify that it is not building a bomb.
But he has always been careful not to define what he means by such a programme and whether that could entail uranium enrichment on Iranian soil. As Iran prepares to activate its first nuclear power reactor at Bushehr this week using Russian-supplied fuel, the White House said on Friday this showed Tehran does not need its own enrichment capabilities. That assertion was swiftly rejected by a senior Iranian parliamentarian.
Whether the US eventually agrees to limited uranium enrichment in Iran will be left to any new nuclear talks, analysts say. Many experts are, however, pessimistic that new negotiations will lead to a breakthrough. "I have major concerns about the absence of Iranian flexibility on the issues that count - and on a parallel lack of flexibility in Washington," Mr Dalton said in a telephone interview. Gary Sick, an Iran expert at Columbia University in New York, questioned in his blog whether "Iran is capable under its current leadership to take a sober decision about how to deal with the outside world".
And there was a "real danger", he added, that "the Obama administration will be so preoccupied with American domestic politics and its constant demand to look tough when dealing with Iran that it will inadvertently rescue this cruel but hapless [Iranian] regime by providing a convenient scapegoat [with sanctions] for everything that goes wrong in Iran." A fourth set of UN Security Council sanctions on Iran in June was followed last month by more onerous unilateral measures imposed by the US and the European Union.
But the impact of the additional US and EU sanctions is likely to be reduced significantly by opposition from Russia, China, India and Turkey. They have said they will honour the UN sanctions but are not obliged to comply with those imposed by the US and EU. Stuart Levey, the undersecretary for terrorism and financial intelligence at the US treasury department, is currently visiting the UAE, Bahrain and Lebanon on a tour aimed at strengthening support for the penalties against the Islamic Republic.