Iran deadline blown again: why the arms embargo is tough to solve

Whatever the merits of Tehran's case, lifting the 2007 UN embargo on the sale of conventional arms to Iran is just not going to fly in the United States.

Is there going to be a deal between world powers and Iran over its nuclear program? Maybe, but certainly not today.

The declared "deadlines" have never been actual deadlines, as was demonstrated once more today in Vienna. But that's a reflection of the high stakes: for Iran, a reduction of sanctions at a time when its economy has been devastated by low oil prices; and for foreign powers, the relief of knowing there won't be another nuclear armed state any time soon and of staving off another possible US-led war in the Middle East.

But now talks are getting down to brass tacks. After all, there's only so many deadlines you can blow through before a process looks doomed. Yet wide differences of opinion remaining between Tehran and at least some of the 5 permanent members of the UN Security Council (Britain, France, US, Russia, and China) and Germany.

The so-called P5+1 is far from united – China and Russia have been eager for a softer deal for Iran so they can get back to selling the country weapons and, in China's case, buying it's oil as soon as possible. The US, not so much. And if President Barack Obama's negotiating team, led by Secretary of State John Kerry, aren't placated, then a deal is not going to get done.

The key problem? An Iranian demand that a conventional arms embargo imposed by the UN Security Council in 2007 be lifted.

Whatever the merits of Iran's case, that's not going to fly within US politics, particularly at a time when both Russia and Iran are already deeply involved in propping up the government of Bashar al-Assad in Syria and Iran's military footprint is expanding deep inside its ally Iraq. There Shiite militias who are receiving Iranian training and equipment are becoming more and more important to the war effort against the Islamic State.

Republican politicians would have a field day – with collateral damage for Democratic politicians like Hillary Clinton who are vying for the White House – and they'd have a point, since Mr. Obama would have caved on an issue that the military has been stridently lobbying against. Chances of Congress approving such a deal? Nil.

Gen. Martin Dempsey, the chairman of the Joint Chiefs of Staff, was blunt when asked about the arms embargo on Iran at a Senate hearing last week. "Under no circumstances should we relieve pressure on Iran relative to ballistic missile capabilities and arms trafficking," he told the Armed Services Committee.

At the same hearing, Defense Secretary Ashton Carter said the Pentagon is particularly worried about Iran's ballistic missile program. "The ‘I’ in ICBM stands for ‘intercontinental,’ which means having the capability to fly from Iran to the United States, and we don’t want that,” he said.

And 2015 is far different from 2007. While the arms embargo wasn't vetoed by China and Russia in the old climate, it's hard to imagine them getting on board again if Iran violates its end of the deal and sanctions are reimposed. Russia, in particular, is no mood to support US-imposed sanctions. The Kremlin has been a US target since President Vladimir Putin ordered the invasion and annexation of Ukraine's Crimean Peninsula last year.

UN Resolution 1747 of 2007 specifically targets both Iran's nuclear and ballistic missile program. It called for Iran to immediately suspend all uranium enrichment and until it didn't, imposed an embargo on military sales to Iran and on Iran's ability to export weapons.

The reality of the situation is that even if Iran verifiably gives up uranium enrichment and allows highly intrusive international inspections, its enemies are not only concerned with nukes. While a possible nuclear weapon has been a top concern, growing Iranian conventional power and influence has been too. And lifting the resolution fast would be an immediate shot in the arm to Iran's regional ambitions. Perhaps a compromise can be found – phased reductions in the arms embargo in exchange for proof Iran's dismantling parts of its nuclear program. But it hasn't been found yet.

One of the advantages of the nuclear negotiation until recently was that it set aside everything but the nuclear problem, and the promise of sanctions that have been damaging Iran's economy in return. The introduction of this demand – if Iran sticks to it – makes a deal much less likely to get done, and an eventual military confrontation between the Islamic Republic and the US more likely.