While Iran may be ready to talk about it's nuclear programme, it is not about to capitulate to US demands.
The US hard line on Iran has left no room to compromise
Listen to Barack Obama explain his Iran policy, and it becomes obvious that the US president has dug himself into a hole.
He's desperate to avoid a war that could be disastrous for America, the Middle East and the world economy, yet he fears that Israel may ignore his concerns and start a fight that could draw in the US.
As a result, the organising principle of his Iran policy appears to be the need to restrain Israel from starting a war - principally by ratcheting up sanctions against Iran, and touting those as a lower-risk option to prevent Iran from building nuclear weapons.
Sanctions are working, say administration officials, imploring the Israelis to give the strategy more time. Look, Iran is feeling the heat and signalling a readiness to talk about its nuclear programme.
But the Israelis, by virtue of their military threat, have a veto.
The problem, of course, is that while Iran may be ready to talk, it is not about to capitulate, particularly given the defiance of Supreme Leader Ayatollah Ali Khamenei, who detests being seen to yield to foreign pressure.
At a Senate armed services committee hearing last week, Lieutenant General Ronald Burgess, the Defense Intelligence Agency chief, bluntly reported that the assessment of the US intelligence community was that despite the unprecedented sanctions, "Iran is not close to agreeing to abandon its nuclear programme."
In the sanctions-as-alternative-to-war logic, that may be a problem, particularly as negotiations are defined as a test of Iran's willingness to cry uncle. Tehran has made clear that it has no intention, right now, of doing that: its nuclear negotiator Saeed Jalili suggested that Iran will return "without preconditions" to the negotiating table with the P5+1 (the US, Russia, China, France, Britain and Germany). That means that Iran won't demand that sanctions be ended before talks start, but it also means that Tehran has no intention of heeding western demands that it suspend uranium enrichment as a basis for negotiations. Indeed, Mr Jalili promised that Iran would bring "new initiatives" of its own to the negotiating table.
Iran has previously signalled support for a Russian proposal of sequential steps by both sides to choreograph an easing of sanctions, and Iranian measures to establish confidence in the peaceful intent of its nuclear programme.
Former Iranian diplomat Hossein Mousavian, currently a scholar in residence at Princeton University, suggested last week that a plausible solution would require western powers to accept Iran's right to nuclear technology, including uranium enrichment, and the removal of sanctions. In exchange, Iran would accept maximum transparency requirements under the Non-Proliferation Treaty (NPT), including intrusive monitoring of all its nuclear work. Tehran would also have to accept limits on its enrichment levels (abandoning enrichment to 20 per cent for medical isotope production) and on the amount of low-enriched uranium it can stockpile - since such materiel can be reprocessed to create bomb materiel - as well as other limits on its nuclear activities during a confidence-building period.
There's no sign that Mr Mousavian's views have the support of Iran's leadership, but if Tehran were willing to move along those lines, that would raise a new headache for the Obama administration, which may have created conditions for itself in which accepting a compromise that leaves Iran with the capacity to build nuclear weapons would be difficult.
Should Iran prove willing to negotiate seriously, the key question will be this: what level of Iranian nuclear capability is the US and its allies prepared to accept, if Tehran satisfies concerns over its previous nuclear work and accepts enhanced inspections and other safeguards against weaponisation?
Until now, Israel and France have insisted that Iran cannot be allowed even the peaceful enrichment capability permitted under the NPT, because of its dual-use potential. The Bush administration concurred, as did the Obama administration initially. More recently, though, the White House has backed a "negotiated solution that restores confidence in the exclusively peaceful nature of Iran's nuclear programme while respecting Iran's right to the peaceful use of nuclear energy consistent with its obligations under the NPT".
It's quite possible, however, for Iran to meet its NPT obligations but at the same time maintain the civilian enrichment technology that would give it the capability to build nuclear weapons. That capacity is currently enjoyed by the likes of Japan, Brazil, Argentina and other NPT signatories. Iran already has that capability, too, although it hasn't yet decided to use it to build bombs, say US intelligence officials. They note that if Tehran broke out of the NPT, it would still take a further two to three years to deploy nuclear warheads.
Still, the political pressures on the US administration are obvious, not only in the Israeli threat of unilateral military action, but also in moves such as the current bipartisan Congressional effort to pass a resolution that would draw the US "red line". That would not be at an Iranian move to weaponise nuclear material, but only at Iran maintaining the capability to build a bomb - which, of course, it already has.
Without Iranian capitulation or military action, the only option left to Mr Obama on this issue is diplomacy. But diplomacy takes time and could involve uncomfortable compromises, which Mr Obama could struggle to make in the face of resistance from the Israelis and their supporters on Capitol Hill in a tough election year.
It may take all of Mr Obama's political and diplomatic nous - and a level of responsible behaviour by the Israelis and Iranians not currently evident in either side's rhetoric - to muddle through to November elections without a new calamity in the Middle East.
Tony Karon is an analyst based in New York.
Follow on Twitter: @TonyKaron