MR. SCHIEFFER: We want to turn now to the week's other big story, the war in northern Iraq and Syria. I sat down with Israeli Prime Minister Benjamin Netanyahu after his address to the United Nations last week. In that speech, he called ISIS and Hamas "branches of the same poisonous tree." So I asked him if ISIS now poses a threat to Israel.

PRIME MINISTER BENJAMIN NETANYAHU: Absolutely. I mean, ISIS has got to be defeated because it's doing what all these militant Islamists are trying to do. They all want to, first, dominate their part of the Middle East, and then go on for their twisted idea of world domination.

The difference between ISIS and Hamas and ISIS and Iran and so on is they all agree that the world should be an Islamist hill, but each of them wants to be the king of the hill. That's what they're really fighting about. Essentially, they want to accumulate enough power to then carry out their mad ambitions. So that's the danger with ISIS. It's creating a state. It's got $2 million petrodollars a day. It's got weapons. It's taken over from the Iraq army, and so on. And it's dangerous, no question. 

But if you think ISIS is dangerous and should be defeated, as I do - and I completely support President Obama's effort and leadership in this regard - then think how much more dangerous Iran is. Iran doesn't have $3 million petrodollars a day; it has $100 million petrodollars a day. And it's working on obtaining nuclear weapons. And that would be, I think, a pivot of history. I think it would endanger the future of our common civilization. So that should be defeated and that should be prevented.

MR. SCHIEFFER: On this battle with ISIS, do you foresee Israel become more directly involved in the battle against ISIS?

PM NETANYAHU: We are ready to support and help in every way that we're asked to do, but these are things that, you know, we don't discuss necessarily on TV, not even on "Face the Nation." 

MR. SCHIEFFER: There's a lot of back and forth about what should we do about Assad and can they defeat ISIS without taking down Assad? What is your sense of that? Should we attack Syrian forces?

PM NETANYAHU: I think right now the real issue is ISIS. ISIS has taken over oil supplies in Syria. It basically uses Syria as a safe haven and as a launching ground for attacks. And, I think wisely, a decision has been made that ISIS targets in Syria and Iraq are equally targetable.

As far as Assad is concerned, I think that you certainly don't have to prop him up and you don't have to cut a deal with him anymore than you have to cut a deal with Iran. They're going to fight ISIS anyway. You don't have to reward them. You don't have to reward Iran with a nuclear deal any more than you have to reward Assad with bringing back the chemical weapons, because he's fighting these guys anyway, as Iran is fighting them anyway. 

So I would say - I wouldn't say what to do - I wouldn't prop Assad up, in any way, and I wouldn't give him immunity, but I would focus the effort on ISIS on one side and preventing Iran from getting atomic bombs on the other side.

MR. SCHIEFFER: How do you describe your relationship with President Obama?

PM NETANYAHU: Actually it's quite good. I have to tell you we had a conversation - I don't want to say like an old married couple, but the president said that he's had more meetings with me than with any other foreign leader. I think you get to a point of mutual respect. You cut to the chase very quickly. You talk about the real things openly, as befitting real allies. I think we have a relationship of mutual respect and mutual appreciation.

MR. SCHIEFFER: Well, let's talk a little bit about Iran. What concerns you most about these negotiations that are going on with Iran?

PM NETANYAHU: Well, from the start I said I don't understand why we should let the world's most dangerous regime, which practices terrorism all the time. I mean, I heard President Rouhani shed these crocodile tears about the spread of global terrorism. He should talk to his own people; they're the ones who are doing it. So this is the greatest terrorist regime in the world, and we don't want them to have the ultimate weapon of terror, which is nuclear weapons.

My fear is that they would get the ability to enrich enough uranium for a bomb in a very short time - weeks, months - and that's the deal that I hope is not signed. And to the extent that you take away the number of centrifuges that they will have left, it becomes a better deal. To the extent you give them thousands of centrifuges, that becomes a bad deal, a very bad deal, not merely for us in Israel but for you and for - I think for the peace of the world. You don't want this regime able to kick out the inspectors, which is what breakout means. They don't care how good the inspections are, they just kick them out and they say, OK, there's, at a time of our choosing, multiple crises around the world, throw out the inspectors, go for enriching the bomb, and you have enough material to make an atomic device which they can put on a container ship and they can bring it to any port in the world. We don't want to be there and you don't want to be there.

MR. SCHIEFFER: Do you miss Ahmadinejad?

PM NETANYAHU: Well, he was telling it like it is. The real leader of Iran is the supreme leader, Ayatollah Khameni. He makes the decisions. He's a dictator, really. And Rouhani is a good front person, you know, and so is their foreign minister. But they don't make the decisions. They're supposed to smooth-talk their way to basically bamboozling the West to get a deal that lifts the sanctions, the tough sanctions that the U.S. has put in place, and that leaves them with enough centrifuges to be able to get to the bomb in a very short time. That shouldn't happen. We've seen sweet smooth-talking foreign minister in the previous century at critical times. That preceded disasters.

MR. SCHIEFFER: As you head home, what most worries you right now?

PM NETANYAHU: I think between East and West - between the great United States, that I would never shortchange and which I think is the leading power in the world, it's a powerful country, it has reservoirs of strength and enterprise and initiative that surpass any other; between the United States and the West and the rising powers in the East - I visited China earlier; I just met with Prime Minister Modi here  these are great events that are happening and are changing our world, obviously. But in between East and West, there is a malignancy of militant Islam whose first victims are Muslims who don't toe the line, and they are cut down brutally; Christians, Yazidis, Jews, anyone secularist, anyone, gays, women. I think that malignancy is growing and spreading. It's sending its tentacles to the West.

I wrote 20 years ago that you will see domestic international terrorists because you'll see them send  jihadists to live in the West in order to wage jihad against the West, andunfortunately that's come about. But the greatest danger that I see from these militant Islamists is that it will marry their mad ideologies to weapons of mass death. That is a threat not only to my people, the Jewish people, and the Jewish state of Israel, but to your people. 

They view us as one because of our tolerant societies that they think of as weak and corrupt. We understand the value of diversity and human freedom and choice. They abhor it. They want to wipe us away. If they have the weapons to wipe us away, they'll try. They'll fail ultimately, as did the Nazis, but they took down tens of millions of people with them. That should not happen again.