Under Secretary of State for Political Affairs Wendy Sherman is back in Geneva, making another go at an interim agreement between Iran and the so-called E3/EU+3. (That’s “E3” as in three European countries: Britain, France, and Germany; “EU” as in European Union High Representative Lady Ashton; and “3” as in the other three: China, Russia, and the United States.)

The purpose of an interim deal is to persuade Iran to suspend part of its nuclear program for six months in exchange for limited relief from international sanctions, while the parties hammer out a more comprehensive deal.

Everything looked set a few weeks ago in Geneva, until French Foreign Minister Laurent Fabius raised some last-minute issues that sent the Iranians back to Tehran for further consultations. The French had a number of concerns — some substantive, others procedural — although early press reporting focused on the nuclear reactor that Iran is completing near Arak. The French were not entirely pleased with the terms of the draft agreement on the suspension at Arak, insisting on tougher language.

Within our own highly polarized political system, this news exploded. Proponents of the negotiations acted betrayed, as if the French had suddenly scuttled the deal. Plenty of pundits retreated to tired geopolitical conspiracies, like the notion that the French were scheming to sell more arms to Saudi Arabia. Opponents of negotiations, who had spent a decade demonizing the French over Iraq and munching on Freedom Fries, were dumbstruck. Vive la France!

But, really, it’s not very surprising at all. Since President Jacques Chirac left office in 2007, the French have become increasingly hawkish on security issues, as evidenced by their enthusiasm for military action in Libya, Mali, and Syria. Americans are from Mars and Europeans are from Venus, huh? You’ll pry nuclear weapons from Marianne’s cold, dead hands.

More importantly, though, the French were right on the merits. A freeze on Iran’s nuclear program needs to include a freeze on construction work at Arak. France’s insistence on a real suspension won’t scuttle the deal. The parties are almost certain to work out some compromise on Arak this week, as part of a broader freeze on Iran’s nuclear program. The deal will be better for France’s intransigence.

Bien sur, Foreign Minister Fabius was wrong to grandstand in public over the terms of the negotiation in Geneva, but politicians do embarrassing things. He was miffed at getting the text just two days before the meeting, suspected the Iranians had already seen it, and saw Secretary of State John Kerry’s presence as an intrusion. Fabius was acting out, but more to the point, he was driving a hard bargain.

That shouldn’t be too hard to understand, yet somehow it is. In the polarized American political system, pundits must either be for every deal or be for none. (Israeli Prime Minister Benjamin Netanyahu even condemned an agreement that had yet to be negotiated!) Americans like to imagine the French are irredeemable cynics, but maybe that just means they’re better at diplomacy than the rest of us. Not everything can be reduced to a matter of principle.

The issue with the reactor at Arak is easy to understand, too. Although most Western observers have focused on Iran’s program to enrich uranium, which offers one path to a bomb, the Arak reactor, called the IR-40, would open a second route to nuclear weapons, using plutonium.

All nuclear reactors produce plutonium. A reactor like the IR-40, which uses heavy water as a moderator, is especially useful for producing plutonium that would be well-suited to a weapons program. Many of the states that have built reactors of this type and size have done so precisely for the purpose of making nuclear weapons, including Israel, India, Pakistan, South Korea, and Taiwan.

The Iranian response to concerns about Arak has been to say that Iran does not have, and will not build, a facility to separate the plutonium from the used nuclear fuel. This is reassuring, but only somewhat. The United States long ago concluded that a state could quickly establish a covert facility to separate plutonium. Any long-term deal with Iran will have to address the plutonium that Iran plans to pile up at Arak.

Until recently, that plutonium was considered a long-term problem. The nuclear reactor at Arak has always been a more distant threat than Iran’s growing number of centrifuges to enrich uranium. But in recent months, Iran has moved closer to bringing Arak into operation. According to a recent schedule provided to the International Atomic Energy Agency, Iran planned to conduct pre-commissioning tests with dummy fuel and plain old “light” water during the last quarter of 2013, and bring the reactor into operation in the first quarter of 2014 — although it reportedly offered to refrain from starting the reactor for the duration of the six-month interim deal.

As best I can tell, under the original draft agreement, the Iranians committed not to bring the reactor online during the interim agreement. They could, however, continue to install equipment at Arak and manufacture fuel for the reactor, bringing it to the brink of operation during negotiations. The Iranians have now indicated that they are behind schedule, and will not have a load of fuel for the reactor before August 2014. In other words, the draft agreement would have allowed Iran to do everything it planned at Arak over the next six months, then start accumulating leverage in the form of plutonium if the terms of the deal were not acceptable. The weeks before Iran loads fuel at Arak will be a moment of maximum danger — the United States and Israel will think long and hard about their last opportunity to destroy the reactor before it is filled with radioactive fuel.

Some observers think the dummy fuel tests are a ruse, a chance to sneak in real fuel under our noses — although I doubt it. A simpler reason to oppose continued work at Arak is that we should only provide sanctions relief in exchange for a real suspension. The West shouldn’t pay for delays that will happen in any event.

This is not some abstract problem. French researcher Bruno Tertrais has carefully explained France’s “tough attitude” toward Iran in terms of its experience dealing with Tehran since 2003. The French have been here before — and with Hassan Rouhani. In 2004, Rouhani negotiated something called the “Paris Agreement ” with the E3, under which the Iranians agreed to suspend their conversion and enrichment of uranium for a few months, while talks continued. The suspension was later extended.

Although the suspension included “all tests or production at any uranium conversion installation,” Iran continued installing equipment at its Esfahan conversion facility. In fact, work never stopped. The commitment to refrain from tests or production was largely symbolic, since Iran was not yet ready to do either — it was still installing equipment.

In 2005, when Iran was ready to start up the Uranium Conversion Facility at Esfahan, the talks stumbled. Iran indicated that it would continue to forego enrichment, but that it would begin the conversion process, producing uranium hexafluoride that could later be enriched. The Iranian talking point was that conversion was never really part of enrichment, anyway. The Europeans realized that the Iranians had gotten the better of them. Frustrated with Rouhani, the Europeans stalled to see whether the Iranian presidential election improved the negotiating environment. Surprise! The Iranians elected Mahmoud Ahmadinejad.

Upon taking office, Ahmadinejad replaced Rouhani and moved quickly to restart the nuclear program. Of course, he was able to do this because Rouhani had arranged the suspension to inflict the minimum delay. The Europeans were not very happy.

Adding insult to injury, Rouhani, now out of office and under attack in Iran, gave speeches and interviews defending his handling of negotiations with the West. (He has also written a memoir.) Rouhani defended himself against hardline critics by arguing that the suspension had been a suspension only in appearance. “We only agreed to suspend activities,” Rouhani told one group, “in those areas where we did not have technical problems.” He added that the suspension actually benefited Iran’s nuclear program “by creating a calm environment” that allowed Iran “to complete the work in Esfahan.” Rouhani admitted that the Europeans were sore about the whole thing: “The day when the Esfahan project was completed and put into operation,” he told the conservative newspaper Keyhan, “the Europeans just began to complain. In a session, they told our experts that we deceived them and did our work in Esfahan.”

You can read Rouhani’s full quotations in the box below. It is hard to read Rouhani’s defenses of his actions, then blame French diplomats for taking a rather, shall we say, Cartesian view of what is, and is not, a suspension. Many of them, like Martin Briens, deputy chief of staff for Fabius, have been working on the Iran file for years. Chat échaudé craint l’eau froide. A suspension in Iran’s nuclear programs needs to include activities at the Arak reactor. Allowing Iran to install equipment and accumulate fuel for the reactor is simply not a suspension. So the French pressed to toughen the terms, including a freeze on the production of new fuel for Arak.

Now, let’s be clear: A negotiated agreement with Iran — even an imperfect one — deserves our support. The people categorically opposed to an agreement are playing a dangerous game. There are few appealing military options, which means the failure of diplomacy is more likely to result in an Iranian bomb than the bombing of Iran. And, in any event, attacking Iran will virtually guarantee that Tehran goes nuclear. This is probably our last, best chance at a deal.

I am not saying that Hassan Rouhani is a liar and cheat. I am saying, however, that Rouhani is politician. A distinction without a difference perhaps, but you don’t get elected president of Iran by being an apologist for Washington. And, if such a person did get elected, he probably couldn’t survive the rough and tumble politics in Tehran very long — certainly not long enough to make a deal stick. Rouhani doesn’t have to be an angel for diplomacy to work. Quite the opposite. The French understand that, which is why they insisted on stronger language regarding Arak.

Americans have a moral streak that doesn’t serve us well in negotiations. Fortunately, the French have no such impairment. Let’s not forget that this is a negotiation: Rouhani is going to try to get the best deal he can. We need to do the same. It’s too bad Dennis Rodman is so busy with North Korea. Even he understands: “Don’t hate the player, hate the game.”

Interview with Hassan Rouhani, by Mehdi Mohammadi, Keyhan,July 26, 2005:

Rouhani:However, from a technical standpoint, the day we started this process, therewas no such thing as the Esfahan project. But as of today, we have prepared andtested the Esfahan facility on an industrial level and produced a few tons ofUF6. Today, we have a considerable number of completed and ready-to-usecentrifuges. On the surface, it may seem that it has been a year and ninemonths since we accepted the suspension. But the fact of the matter is that wehave fixed many of the flaws in our work during this period. We continued ourproduction and assemblage activities until the time of the Paris agreement. Itis true that at a certain juncture between February and June 2004, there was apause in this process according to the Brussels agreement. But after June, wemade up for that pause with extra effort. We didn’t suspend the Esfahanproject for even a moment until the project was completed and tested and itsproduct was achieved. The Arak project was never suspended either.

Mohammadi:Dr. Rouhani, could we say this as a general rule — that as long as atechnology or a facility of ours was incomplete, we wouldn’t accept to suspendit, and wherever a project was suspended, we already knew for sure that we wereable to complete it.

Rouhani:Practically, this was the way it turned out. But the matter that weconstantly had in mind was that when it came to suspension, we should sufficeto the minimum extent, in order to suspend as little of our activities aspossible. More importantly, when a certain activity was suspended, during thatperiod we would concentrate all of our effort and energy on other activities.So the right thing to say is that wherever we accepted suspension, beside thatwe thought about another area of activity. The day when Natanz was suspended,we put all of our effort into Esfahan. Now that Esfahan is in suspension, weare fixing other existing flaws. Of course, we didn’t adopt a high profile onthis matter, though we always seriously though about an atmosphere of workalong with the suspensions. The day when the Esfahan project was completed andput into operation, the Europeans just began to complain. In a session, theytold our experts that we deceived them and did our work in Esfahan. Buttoday, as you see, the political consensus that had formed against Iranat the outset has completely broken. Even the Americans, who always believed under no circumstances should they deal with Iran through negotiation and interaction, have now reached a point where they say not only that theysupport Europe’s diplomatic talks with Iran, but also they are ready totake certain measures to contribute to the process. So that consensusagainst us doesn’t exist any longer.

HassanRouhani, “Beyond theChallenges Facing Iran and the IAEA Concerning the Nuclear Dossier,” Rahbord, September 2005:

Anotherdevelopment was that the Europeans gradually reached the conclusion that we hadnot accepted suspension in areas where we had technical problems. We onlyagreed to suspend activities in those areas where we did not have technicalproblems. This is what they are saying now in their negotiations. We completedthe Esfahan project, which is the UCF where yellowcake is converted into UF4and UF6 during suspension. While we were talking with the Europeans in Tehran,we were installing equipment in parts of the facility in Esfahan, but we stillhad a long way to go to complete the project. In fact, by creating a calmenvironment, we were able to complete the work in Esfahan. Today, we canconvert yellowcake into UF4 and UF6, and this is a very important matter