RACHEL MARTIN, HOST:

The war against the self-declared Islamic State has created some unusual partnerships. This past week, ISIS took control of the city of Ramadi in Iraq. It's a significant blow to the Iraqi security forces. Now, those forces have partnered with Shiite militias to retake the city. Vali Nasr is the dean of the Johns Hopkins School of Advanced International Studies. He says these militias, which are backed by Iran, are a more effective fighting force than the Iraqi military. But that reality, he says, creates some difficult political complications for the United States.

VALI NASR: The way we think of the Shia militias is actually something of an Iranian instrument. The way the Shia population sees it is that this is the actual force that's going to protect them. It comes from among them. It has the backing of politicians. It has the backing of clerics. It's operating on the basis of actually a religious call to action. And it has also proven itself effective on the ground. So, you know, we don't like the Shia militias because we have problems with Iran. We want to sort of have a neat and tidy narrative that we're working with this sort of professional, secular, national Iraqi security force, which has been proven in Mosul and Ramadi and Tikrit really that it actually doesn't exist. It is increasingly a figment of America's strategic imagination.

MARTIN: So are you saying the United States needs to just wake up to the reality that it actually is allying, to some degree, with Iran when it comes to fighting ISIS in Iraq?

NASR: Well, we definitely have common interests with Iran in not only Iraq, but increasingly Syria. I mean, the reality is that our Arab allies are fighting a very different war. ISIS is blowing up mosques in Saudi Arabia, and yet the Saudis' primary strategic concern is bombing Houthis in Yemen, which means their party is different from ours. In Iraq and in Syria, the United States is not there out of altruism. The United States is there to protect itself against instability and the scourge of terrorism. So it's not true that this is an Iraqi problem. This is an American problem because if ISIS takes over this vast area and creates a massive ISIS nation state, then it's going to destabilize the rest of our allies. And the problems will visit on Europe and the United States.

Now, if this is the goal to defeat ISIS, to deny it the ability to carve out Syria and Iraq into a single Sunni state or a worst-case scenario, that it takes over Damascus and Baghdad as well and creates a much larger behemoth, then we have to see how can we do this? Either we deploy hundreds of thousands of American troops on the ground as we did in Afghanistan to take the Taliban out of power in 2001, 2002, or we have to see what force is actually fighting on the ground. Who is actually doing the effective fighting? And we can try to avoid what is the two-ton elephant in the room, which is the effective fighting is happening by Shia militias trained, backed and armed by Iran.

MARTIN: You know, U.S. officials will try to frame this as a regional issue. And it is a regional issue in many different ways. What do you think then is the responsibility borne by those gulf countries - Qatar, Bahrain, Saudi Arabia, the Gulf states? Should these countries be stepping up in a way they haven't yet against ISIS?

NASR: No, they haven't stepped up in the way ought to. First of all, there is a history of tacit support to radical elements in Syria and Iraq, encouragement of tribes to resist essential government or to join hands with the extremists that helped actually create ISIS into what it is today. You know, we had a Camp David meeting, which was about Iran. We didn't have a Camp David meeting with the Arab governments to get our ducks in a row about ISIS. And I think part of the blame lies with the administration that has not made this into a priority in its conversation with regional governments, demanding of them certain change on strategy to address the ISIS problem.

MARTIN: What tactically should the U.S.do that's not doing now?

NASR: Well, the reality is that we will have to do more of what we did in Tikrit, which is American air cover allowing the Shias to fight. And the more honest we are about this, the more effective our campaign would be. So complicated strategic situations like Iraq calls for strange bedfellows. I don't think the Iranians like being seen in cahoots with the Americans any more than we like being seen in cahoots with them.

But the reality is we both view ISIS as a mortal danger to our interest. And we both see that there is no alternative right now to this kind of tacit, unspoken of American-Iranian coordination. So American airpower does provide support to Shia militias that are armed, backed and trained by Iran's revolutionary guards. For so long as these Shia militias are the only possible response to ISIS, I don't think we have another option; unless we either wash our hands of Iraq and Syria and say whatever happens, happens. We don't care. Or that we say we'll have to do this ourselves. We actually have to put a lot more troops, money and resources into doing the fighting on the ground. And I don't think the American public would like that going into an election season. Nor is the American public actually being made aware of this reality that you don't have the luxury of some magical Iraqi security forces doing this for you.

MARTIN: Vali Nasr is the dean of the Johns Hopkins School of Advanced International Studies. He joined us in our Washington Studios. Thank you so much.

NASR: Thank you. Transcript provided by NPR, Copyright NPR.