At the State Department in Washington on Monday, Secretary of State John Kerry welcomed Bruno Rodriguez, the foreign minister of Cuba. Later in the day, Kerry sat down with Morning Edition host Steve Inskeep to discuss the U.S.-Cuba relationship, and the pact that recently was negotiated with Iran regarding that nation's nuclear program.

STEVE INSKEEP: Some weeks ago we spoke with Marco Rubio — who's running for president, one of the Republican candidates — who said, and I think he's not the only candidate who said this, that if elected he would reverse the Cuba policy. That he would break off diplomatic relations with Cuba. Can the next president, in practical terms, undo what you have done?

U.S. SECRETARY OF STATE JOHN KERRY: Well, any president has, obviously, the ability to make a decision. Congress, obviously, has the ability to have an impact on that. But I think it would be a terrible mistake. The vast majority of the American people believe this is a very good thing to do.

It doesn't make sense — I mean, we had diplomatic relations with the Soviet Union; we had diplomatic relations with then-called Red China. We have to have relationships with countries to do business, and American citizens get hurt when we don't do that.

Given the fact there are so many Cuban-Americans, people who have family in Cuba, to not have a relationship where we can advocate for people — advocate for human rights, advocate for fairness, for elections, for democracy, for travel, for engagement, all these things that make a difference in the quality of life of Cubans — would be a terrible, terrible mistake. So I think, as time goes on, people will see the benefits that come from this policy.

Well that raises another question: Now that you have a nuclear deal with Iran, could you envision a circumstance where you would stand with Iran's foreign minister, Javad Zarif, announcing the reopening of formal diplomatic relations, the way you just did with Cuba's foreign minister?

Well, could I imagine it? I'm sure I could conjure up some imagination — but has to be way off in the future, with a huge amount of changes from where we are today.

What does Iran have to do to make that happen?

Well, Iran has to engage with the world, and make it clear that it's going to stop supporting terror and stop exporting weapons to terrorists, and engage in activities that join the community of nations in a constructive way.

Well, that leads to another question, also: Will the nuclear deal make Iran, in effect, more powerful? Because Iran has given up some nuclear research progress in exchange for $100 billion in unfrozen assets and a lot of other benefits.

Well, it's given up a lot more than that. I mean, Iran without a nuclear weapon is a very different Iran than one with one, and this is why many of us are so amazed at the reaction of some people.

Israel, for instance, is much safer without an Iranian nuclear weapon. And we believe that what we have done in this deal — and even before this deal, in the last two years — is roll back Iran's nuclear program. Before we became engaged with Iran, they had a two-month breakout time. Now they'll be going to a year breakout time. Is Israel safer with a year, or aren't you? I mean, this is pretty straightforward.

So, the fact is, we'll have inspectors in the country; we'll have restraints on what [Iran] can do, in terms of levels of enrichment, restraints on the size of their stockpile, restraint on their research and development. Clearly people are safer with those restraints in place — and forever, for lifetime, they have to live up to the access under the additional protocol of the IEA, they have to have huge restraints on the uranium production and other things.

So I believe over time we will show people in the Congress and elsewhere in the country that Israel, the Gulf states, the countries in the region are much safer with this deal than without it.

Iran will also have a much larger economy, presumably — which is good for the people of Iran, but won't that allow it to project its influence even more forcefully throughout the region?

No, for a number of different reasons.

First of all, a lot of people are ignoring the fact that there's a pretty natural divide between Persia and the Arab world. There's also a divide between Shia and Sunni, Sunni being the vast majority of the Arab world. In addition, there are other stakes here, which will change things, in that if Iran continues to support these bad activities, we have agreed with the Gulf states that we are going to push back, intensely.

We're going to do additional training with those Gulf states; we're going to provide them with counterterrorism training, with special forces operational training, with cyber, with other capacities.

So the region will gain in stability; if Iran chooses to engage in these activities, they're going to find a very different pushback than has existed in the previous years.

When you say Gulf states, you're talking about which ones, specifically?

I'm talking about all of them, the Gulf states — you know, the GCC, the Gulf State Cooperation Council.

And you're saying you have an agreement now that, if Iran misbehaves, you will be taking these further steps together —

Well, we're doing more than that. We're not even waiting for mis-

We're, based on their past behavior, we are engaging with the Gulf states in greater training and preparation activities — this is what Camp David was about, the meeting that we had, summit we had, several months ago.

And we all — I mean, look. Hezbollah is a designated terrorist organization; Iran supports it. There's a U.N. resolution that prevents Iran, technically, from shipping weapons to Hezbollah — that hasn't happened, worked, has to be enforced. Likewise, Iran is not allowed to send weapons to the Houthi, in Yemen. There's another U.N. resolution about that — has to be enforced.

So we are going to engage with others in making sure that we hold Iran accountable to standards that it must be expected to live up to.

Do you feel you are actually freer to push against Iran than you were before?

Absolutely, in many — well, not freer in the sense that I believe we're free to do this, because that's clearly not part of our agreement; all we did was negotiate a nuclear restraint. And the reason is very straightforward: If you're going to push back against Iran, it is better to push back against an Iran without a nuclear weapon than one with one.

Pretty simple proposition, and you would think that the states in the region would actually think about that a little more.

I want you to have an opportunity to answer a common criticism that's been made of these negotiations: that President Obama was too eager for a deal, that Secretary Kerry was too eager for a deal, and made that too plain. That you would pay a high price for a deal. That's the criticism that was made.

In light of that I'm wondering, in looking back at your negotiations with Javad Zarif, the Iranian foreign minister, and others — can you recall a moment when you were prepared to walk away, or even said, "we are walking away"?

Well, let me tell you what a complete and total fallacy that criticism is. It's totally made up by people who somehow want to find a way to criticize the agreement. Because the fact is that I walked away three times. And we were more than ready to walk away in the end, as I made clear on Sunday when I came out before the cameras and said "if things don't change, we're going home." And I told that to my counterpart. I suppose, I suppose we were so eager, that's why it took four years to negotiate.

I mean, really, it's one of the dumbest criticisms I've ever heard in my life, because it has no relationship to reality of what we were engaged in. President Obama, in almost every conversation, would say, "remember, John, you can walk away."

And I did walk away. In London, I walked away when they started fudging numbers they'd already agreed to and they moved backwards. I walked away again when we were in another set of talks in Lausanne. And I walked away most recently — I told my counterpart that if things didn't change and we didn't move, we were going home. So we had no compunctions about it whatsoever.

No, I think the fact is, we got the deal that was achievable beyond people's belief. And that's what you heard from people after we announced Lausanne — they were surprised at the detail and what we got.

Guess what: We actually strengthened that when we went to Vienna, and I think that we have restraints here on weaponization, restraints on mechanical testing, restraints on metallurgy, restraints on their centrifuge production, restraints on their mining, their milling, their yellowcake, their — I mean, all through the fuel cycle. We have restraints on their RMD. We have a remarkable set of understandings of what they can do and can't do, and we will have the ability to inspect and know what they were doing.

And if the Congress kills this deal, there will be no restraints — none whatsoever — no inspections, it's over, and the sanctions will disappear. Because our colleagues who we negotiated with will say, "Well, look, the United States Congress killed this, we didn't — but now everybody's free to do what they want."

You have said that the world would be on a path to conflict —


—"almost immediately," was the quote, if Congress rejects this deal. How does that happen? How does a path to conflict begin almost immediately?

Well, let me tell you exactly what happens. If we — if the United States Congress says, "No, this deal isn't going forward," and they actually got enough votes to kill the deal, there's no deal. If there's no deal, there are no sanctions, there are no inspections, there's no regime hanging over Iran — except the existing IEA, which wasn't enough to get the job done, which is why we negotiated something further.

And Iran will say, "Aha, you see!" The Ayatollah will say, "I told you, you can't trust the West. I told you, you can't negotiate with these guys. They will lie to you, they will cheat you, and here they are — they led us down the path and the Congress walked away. They have 535 secretaries of state; there's nobody to negotiate with."

And our European allies will walk away saying, "Well, we tried our best, now we trust Iran and we're going to go do something." And they'll cut their own deal. We're finished.

I'm telling you, the U.S. will have lost all credibility. We will not be in the hunt, and if we then decided to use military, do you believe the United Nations will be with us? Do you think our European colleagues will support us? Not in your life. They'll say "you guys just walked away from something we spent four years negotiating with you."

This, this will be a travesty, and Iran will begin enriching, claiming it is a right which they only gave up in the context of negotiations — but since the negotiations are dead, they're going to resume their rights.

And then you are right into conflict, with presidential candidates screaming at Obama: "What are you going to do now? You've got to bomb them! You've got to use military force!" And, you're going to — and Israel's saying the same thing — and you'll see another $20 million spent to convince people that's what they have to do.

Are you — since you mentioned presidential candidates — are you comfortable with the idea of the 2016 election being, on some level, a referendum on this nuclear deal? Because many Republican candidates have said they would scotch it if they get into office.

Well, let's see where we are when Congress finishes this debate. I really think that, on the merits, this deal makes the world safer.

Do you think the critics are not serious, and they'll just move on to other issues?

No, I think they'll continue to bang away if they think they've got an issue that — we all know that politics in America isn't exactly on the up-and-up these days. So I'm sure that they'll do what they want to do.

But the fact is that this deal is the only way in which Iran's program has been rolled back — and when, in the last administration, they had a policy, obviously, of no enrichment, we watched the program grow. Not blaming anybody; it's just what happened. So as a result of that, we know that, unless you have serious restraints on the enrichment, they're going to grow it.

We have those restraints on that enrichment. We have a limitation for 15 years of the size of their stockpile. We have a limitation for 15 years on the level they can enrich to. We have a limitation for 25 years on the nature, the monitoring and production of their uranium. Our intelligence community tells us it would be absolutely impossible for them to be able to develop an entirely separate, secret track for fuel production. So they can't create a covert weapon.

So we think we have really done something quite unique here, which is create a methodology for holding this country to what it's promised, which is not to have a nuclear weapon. And I think to scotch the deal, to get rid of it — arbitrarily, unilaterally — would be to make the world a more dangerous place.

Two quick questions and I'm going to let you go. The people have raised the question of trust, quite often, and said, "You can't trust Iran."

That's right, you can't trust Iran — and nothing in this deal is based on trust.

The administration has responded, "Don't have to trust them, we're going to inspect them."

But you were there negotiating. On some level, don't you have to trust that somebody in the room is serious? And did you, in the end, trust that you were dealing with serious people who really wanted an agreement that would last?

What you have to trust are the words that you get on a piece of paper that allow you to do something or don't allow you to do something. And you have to trust that those words are going to be implementable by you — yourself.

That's what we trust. We trust that we have the ability to enforce this deal; we trust that the deal, if implemented, will do the job. And if it's not implemented, we trust that we have every option available to us that we need.

Final thing, Secretary Kerry.

Your name has come up in the news in an unexpected way the last few days: Donald Trump, Republican presidential candidate, criticized the war record of Sen. John McCain, saying he was only a war hero because he was captured. Other Republicans immediately criticized that, which has caused people to remember that a number of Republicans criticized your Vietnam War record when you ran for president in 2004.

Do you have any thoughts about this debate?

I defended John McCain because he's a war hero, and I think the comments were, obviously, inappropriate. But the rest of it is ancient history.

Meaning you don't hold anything against the Republicans?

Copyright 2016 NPR. To see more, visit