Joe Cirincione is the president of the Ploughshares Fund and the author of the new book "Nuclear Nightmares: Securing the World Before It Is Too Late."

Six nations were prepared in Geneva to make an interim deal; one nation was not. The French concerns have now been incorporated into a new draft agreement, but it was different enough from what has been worked out over the last few weeks that the Iranian negotiators had to go back for further consultations.

But there is now momentum behind a deal to constrain Iran's program while providing it with some limited relief from sanctions. There was tremendous progress in Geneva. Ministers from all seven nations met in marathon sessions to narrow the gaps, and committed to having their teams return in a mere 10 days. The strategic imperatives driving toward an agreement are strong; the negotiating teams from both Iran and the United States are perhaps the best we could imagine.

We have come a very long way in the past two months. We now accept as normal that the U.S. secretary of state should engage in hours of discussion with the Iranian foreign minister. But that hasn't happened since the shah. It happened for the first time at the United Nations in September, and then for only one hour. The U.S. and Iran negotiated more in three days in Geneva than they had in three decades.

All the nations were in agreement, and a draft agreement had been worked out, until French Foreign Minister Fabius arrived and threw a croissant in the spokes. He took a maximalist position, according to some observers on the scene, and insisted on conditions Iran could not meet. Other members of the P5+1 were reportedly furious at Fabius.

The differences appear to be largely over the issue of the Arak reactor. This reactor is not scheduled to go online until the end of 2014, is already behind schedule, cannot produce plutonium for a year after that, and Iran does not have a reprocessing plant that could extract the plutonium. It is a problem, but not a near-term proliferation threat. Fabius wanted it shut down now.

Kerry made clear that the reactor would have to be part of a final agreement. But that is different from making it part of this limited initial step. The French approach is the difference between making demands and making a deal. Yes, there is a list of issues we must resolve; no, we do not have to resolve them all in the first step.

The plan is for a phased agreement: Iran stops certain activities; the others relax certain sanctions. As more activities are stopped, more sanctions relief is granted. France overloaded the cart. We now have to unload it a bit, or if we want Iran to do more, we have to be prepared to offer more sanctions relief. There is agreement on the main components of the deal; we are now bargaining over the ratios.

U.K. Foreign Minister William Hague told parliament on Monday that there was now a solid Iran deal "on the table, and there is no doubt in my mind that it can be reached." I agree. We are very close to a deal. It's coming. It will just take a little more time.