By all accounts, the talks this weekend in Istanbul between the major powers and Iran are critical if diplomacy is to solve the crisis over Iran's suspect nuclear activities.
A breakdown in the talks, the first between Iran and the "P5+1" group (the five permanent members of the UN Security Council -- Russia, China, Britain, France, the United States -- and Germany) in more than 1 1/2 years, could dramatically increase the risk of a military confrontation with the Islamic republic. Israel has suggested that it would act unilaterally to bomb Iran's nuclear sites if the status quo continues.
U.S. Secretary of State Hillary Clinton maintained this week that the talks, which were beginning officially on April 14, would give Iran the chance to address "seriously" the concerns of the international community over its nuclear program.
"We believe there is still time for diplomacy," she said. "But it is urgent that the Iranians come to the table to establish an environment conducive to achieving concrete results through a sustained process."
As the result of the unprecedented harsh sanctions that Iran is facing, including a European oil embargo due to take effect on July 1, Western countries were hoping that the country's leaders would be willing to take steps to ease concerns over Tehran's possible nuclear weapons program.
A key step would be a halt in Iran's production of 20 percent-enriched uranium at the underground Fordow nuclear facility near the city of Qom, and the transfer of existing stocks away from the country.
Uranium enriched to 20 percent can be used for civilian nuclear programs, and from that level can more easily be enriched to weapons grade. Tehran insists its nuclear program is used for peaceful medical and energy purposes.
Iran has in the past ruled out the suspension of its enrichment activities, as ordered by the UN Security Council.
Nonetheless, the head of Iran's Atomic Energy Organization, Fereydoun Abbasi Davani, hinted recently that Tehran could eventually stop its production of 20-percent enriched uranium needed for a research reactor after it had produced enough of the material.
Going forward, it would then enrich to lower levels for power generation. Davani was quoted as saying that enrichment beyond 20 percent was not part of the country's long-term nuclear goal.
Iran's chief nuclear negotiator Said Jalili
Iran's chief nuclear negotiator, Said Jalili, who was to be leading the Iranian delegation at the talks, has said they will bring "new proposals" to the table, without providing details.
Michael Mann, chief spokesman for EU foreign-policy chief Catherine Ashton, told RFE/RL that the P5+1 negotiating group wasn't expecting any deals to come out of the talks.
"It's just the first, we hope, of a series of negotiations," he said. "[It will involve] building confidence, getting the atmosphere right, putting the issues on the table, and hopefully we can kick off a process that will last and we can go into a second round of talks, a third round of talks, and really make some progress."
'The Clock Is Ticking'
Shannon Kile, a senior researcher at the Stockholm International Peace Research Institute (SIPRI), maintains that Western countries are looking at putting in place a longer-term diplomatic process.
"That's very important because the window for diplomacy is closing now," he says. "The clock is ticking and this really maybe is the last best chance for diplomacy, for a diplomatic solution to the Iranian nuclear controversy.
"And so I think what we're going to see this time is a much greater willingness to be patient, to understand that this is going to be a longer-term process, and that there is not going to be any quick solution in one weekend in Istanbul."
John Limbert, a former deputy assistant secretary of state for Near Eastern affairs and one of the 52 Americans who were held hostage in the 1979 Tehran hostage crisis, insists that diplomats in Istanbul should keep their expectations low and have "a lot of patience," because of the high level of mistrust and hostility in relations between Iran and the West. He also suggested that signs of success at the talks could be subtle.
"Maybe success is an agreement to meet again," he says. "Maybe success is something not said. Maybe progress is a handshake. One thing I would look for, for example, is: Is there going to be a bilateral meeting the Iranians and the American heads of delegations? If there is not, then I think there is a problem."
Rattling Sabers And Punishing Sanctions
Previous nuclear talks with Iran have failed due to Tehran's unwillingness to compromise. But there were suggestions that the combination of saber rattling from Israel and punishing economic sanctions from the West might produce a different outcome in this round.
Ali Vaez, an Iran analyst at the International Crisis Group, says he is "cautiously optimistic." In his view, the "enrich what we need" condition could give the Iranians a face-saving solution for stopping its 20 percent-enrichment program.
Hossein Alizadeh, a former Iranian diplomat who resigned from his post in 2010, told RFE/RL's Radio Farda that Iran was likely to show flexibility during the Istanbul talks, not just because of increasing pressure from abroad but also at home.
Nonetheless other observers, including Washington-based Middle East expert Rasoul Nafisi, aren't as optimistic.
Nafisi says Iran is coming to the table again with "the old strategy of buying time" precisely because of the military talk and biting sanctions. In other words, he argues, they're looking for a way to lessen the pressure without giving anything up.
RFE/RL correspondents Irina Lagunina and Rikard Jozwiak contributed to this report