President Obama has called this agreement “historic;” Secretary of State Kerry says it’s a “milestone.” Are they correct?

I do think that the agreements represent a critical step forward, without which all of the concerned countries would have faced an uncertain, and possibly bleak, set of scenarios. Moreover, what has surprised everyone, even opponents of the deal, is that this agreement has far more detail than anyone expected. It sets out a framework that on many issues is quite robust.  That comes against a background in which all the participants basically agreed that they had no alternative to failure. The longer we have walked down the path of diplomacy, the greater the costs of not reaching an agreement. This pragmatic calculation is what counts.

Is pragmatism enough? After all, what you just described could also be desperation dressed up in diplomatic language.

That’s a legitimate point. I think critics of a deal saw the days and days of endless haggling either as evidence for the futility of the entire process or as a prelude to a vague agreement. Even though this accord has a surprising amount of detail, it also has plenty of vagueness and ambiguity. So a lot has to be negotiated between now and June 31, the formal end-date for the talks. But each side, the U.S. and Iran in particular, got enough specifics that they can defend the document and the overall diplomatic process back home. And what everyone got is a document that is sufficiently substantive to serve as the backbone for a series of negotiations that won’t be easy, but now has better chances for success.

The accord announced yesterday is called a “Joint Comprehensive Plan of Action.” What are its key elements or provisions?

On enrichment, Iran has agreed to reduce its installed centrifuges by two-thirds—to about 6,000—and to limit their enrichment of uranium to 3.67 percent.  It has agreed to send spent reactor fuel out of the country, which had been a disputed issue in the talks. And, it has promised not to re-process fuel—in perpetuity, it would appear. These limits are pretty much what was expected, perhaps a little better.

Just a follow-up on enrichment:  The State Department says the agreement extends Iran’s “breakout time” from what now is about two to three months, to about a year. Is that right? That may be sufficient for the negotiators, but will it be sufficient for critics of a deal?

“Breakout time” means, technically, the amount of time that Iran would need to build a bomb if it chose. In particular, it measures the time Iran would need to enrich enough uranium to fuel one nuclear device.  It was widely reported prior to the Lausanne negotiations that the key parties had agreed on one year, and so there is no surprise here.

But we hear a number of critics saying one year isn’t enough.

Yes, the most vociferous critics reject any deal that allows for enrichment, so you can’t please them. Effectively, they are demanding an unfeasibly long “breakout time” as a deal breaker.

But keep in mind that even after Iran had enriched enough uranium, it would need at least two years to actually have a deliverable weapon. Moreover—and this is a point that critics of the deal don’t dwell on—the concept of “breakout time” is not so much a technical as it is a diplomatic device. It assumes that we all agree (and know) from the outset what Iran has in terms of enrichment capability and stockpiles. And it supposes that Iran at some point might quite deliberately and publicly declare or show that it is going for a weapon, which would invite immediate diplomatic and possibly military retaliation. So we’ve created this notion of a “breakout” as a device that will state what each side can live with—even as the assumptions behind it are not at all compelling.

The real challenge is not to prevent breakout but “sneak out”—that is, clandestine efforts to acquire or produce high enriched uranium, and that just for a start. To prevent this, what counts is a robust regime of monitoring and inspections of all key sites, particularly Natanz, Fordow and the unfinished reactor at Arak.

So what about the inspections provisions?  Are they enough to block clandestine activities?

Experts will have different assessments. But let’s consider this: Iran has agreed to not enrich uranium at Fordow for 15 years and to convert that site into a research facility. It will limit enrichment at Natanz to 5,050 older-generation centrifuges. And it will re-design and rebuild the heavy-water research reactor at Arak so that it cannot produce weapons grade plutonium. To permit verification of all this, it has accepted a set of robust inspections and monitoring systems that go well beyond what is expected of NPT [Nuclear Non-Proliferation Treaty] signatories. Altogether, this is impressive.

So if everything is so good, why do some folks worry that it might be so bad?

Hold on, I didn’t quite say that or mean to imply it. There’s a lot in the agreement that remains vague, and that will require very difficult negotiations to nail down. There has been some measure of kicking the can down the road, and in some cases this is a big can for what remains a fairly short road—until the end of June.

So, what are the big cans?

The first has to do with what negotiators call “possible military dimensions,” or PMD, of Iran’s nuclear activities. The IAEA [International Atomic Energy Agency] has not been happy with Iran’s most recent responses on this and said as much. The plan announced yesterday states that, for sanctions to be removed or reduced, the IAEA must have “verified that Iran has taken all of its key nuclear related steps.” Iran may object that PMD questions don’t fall under this, and/or may simply not provide the information that IAEA wants. This is a real challenge.

Of course, that raises the sanctions issue.

Yes, indeed, and let’s be clear. The sanctions issue has been the really difficult and big challenge, the potential deal breaker all along. The Iranians had demanded that all sanctions—especially the sanctions voted on by the UN Security Council in a series of six resolutions—be removed upfront. The U.S. and most of its allies—and I believe, the Russians and the Chinese as well—want to remove sanctions in response to a series of steps, the completion of which would then bring about some but not all sanctions relief. Iran’s Supreme Leader made statements that seemed to suggest that Tehran’s position was something of a red line. In many respects, the U.S. position also seemed like something of a red line, especially for Congress, which of course put the sanctions in place.

Has this agreement bridged that divide?

I suppose that depends on how you read the six sanctions-related lines in the agreement. Critics will say that they lack the clarity and mutual reinforcement that would chart an unambiguous map for dealing with the sanctions issues.  This is not an unreasonable criticism, but neither is the ambiguity surprising, because sanctions were the biggest sticking point.

From Tehran’s perspective, the language is a partial victory in that it can be read to suggest quick sanctions relief as soon as Iran’s compliance has been verified. Still, there’s enough fuzziness to support other interpretations. The deal says that, if Tehran “fails to fulfill its commitments, these sanctions will snap back into place.” That could make it harder for the negotiators to defend the deal in Tehran, while making that task easier in Washington. So on sanctions, there are hard negotiations to come.

We’ve had a lot of debate over the length of the agreement.

Critics of the agreement have repeatedly raised the length of an accord and any possible “sunset” clause that might terminate it. Overall, the text announced yesterday suggests a 10-15 year period for the agreement. From Washington’s perspective this is very good, and perhaps better than anticipated.

Some opponents of the deal have argued that Iran would be free to do whatever it wants after this period. This point has been misrepresented or at least misunderstood. The length of the agreement refers to a series of extraordinary measures—inspections and the like—that go far beyond the requirements of the NPT and the IAEA. Whenever the extraordinary restrictions on Iran’s nuclear activity are removed, 10 or 15 years from now, Iran will still be subject to an entire set of constraints and inspections, as is any member of the NPT that engages in enrichment. The 10 to 15 years is a testing period to ascertain whether Iran can and should be subject to the normal conditions of NPT members. If it fails this test, it will face the very consequences it has endured for decades.

So are the critics of this deal being unfair?

There is certainly room and reason for skepticism. Critics will say that Iran has cheated before and can’t be trusted. There is ample justification for demanding very stringent conditions on Iran and for linking its compliance to reducing or eliminating sanctions over time. But there is a difference between opposing an agreement because it’s not adequate and opposing it because you reject, in principle, any agreement under any conditions that would let Iran have even a measure of enrichment. My sense is that a lot of the opposition to an agreement is fueled –sorry for the pun—by the belief that no agreement that doesn’t force Iran to capitulate is acceptable. They want and insist on “zero enrichment.” But of course, agreements by definition must be based on compromise, so this positon is really advanced to block an agreement. The U.S. effectively enabled this positon for many years, seeking or preferring zero enrichment while Iran’s centrifuge program expanded dramatically.

So, was this self-defeating?

Yes, indeed. In so many ways, sticking to a position that precluded diplomacy undercut our position and even made a negotiated solution more difficult, since Iran went from 164 centrifuges in 2005 to about 20,000 machines now, 10,000 of which are operational.  Obama and his administration took the courageous step to exit this diplomatic cul-de-sac. They realized that it left the U.S. and its friends with two equally unpalatable choices: containment or war.

Israel has been implacable in opposition to this deal. Do you think that it or, say, Saudi Arabia, another Iranian rival and close U.S. ally, actually wants an attempt at a military solution?

That’s a tough question. Israel’s political leadership sees Iran as an existential threat. This judgment is not completely shared by the country’s military experts, but it’s certainly a common sentiment of most Israeli citizens. Saudi Arabia and other Gulf Arab states see an agreement as a signal of a fundamental strategic shift toward Iran that they feel is dangerous for them. They are alarmed. For all these countries, the notion of a diplomatic solution that included even the toughest monitoring of Iranian nuclear facilities was not acceptable. They wanted Iran’s nuclear program dismantled.

Wouldn’t that be a good thing?

Sure. But that kind of total capitulation by Iran is a non-starter. This position leaves you either embracing the war option or slipping into containment. No one wants the second option.

As for war, let’s be frank: There is no quick military solution. U.S. military experts tell us that even a full-blown military campaign would offer no guarantee of strategic success.  Diplomacy isn’t always the answer, but in this case, we have a remarkable international coalition of countries that have embraced negotiations as the best way forward by comparison to the alternatives. This is common sense and I think that with a bit of luck and considerable political will, diplomacy will win out.