BERLIN —"Understanding your opponent's agenda will help you in defeating him," says German scientist Johannes Siebert. He's the only German on a Pentagon-recruited team tasked with better understanding the objectives of ISIS. This expert in behavioral operations at the University of Bayreuth in Bavaria has come to a completely unexpected conclusion.

DIE WELT: How did you get the job at the Pentagon?

JOHANNES SIEBERT: I am specialized in decision theory, which allows me to investigate how executives and leaders make their decisions by identifying and structuring their goals. When ISIS started to spread, I was wondering if I could be of any use in fighting them. At CREATE (the Center for Risk and Economic Analysis of Terrorism Events at the University of Southern California), I had the possibility to do so.

Scientists from different disciplines contribute with their know-how in order to improve protection of civilians. And by chance, on my first day of work, CREATE was assigned by the commander of the U.S. military force in the Middle East the task of finding out why ISIS was so attractive for its followers, and what goals the organization was pursuing.

And what were your findings?

It's about the creation, and conservation, of a caliphate in Syria and Iraq. That's the military aim. And the religious goal says: spread Sunni Islam. Therefore we're not only talking about a sect misusing religion, but an organization making a territorial leadership claim. In order to get there, other goals need to be reached — generate money and followers, kill the so-called "non-believers."

But that's nothing new.

But it makes a huge difference. A solely religious organization has fewer chances of finding supporters. A state is much more attractive. It's easier to find support, and therefore money, to finance the terror. They are trying to establish a state-like structure. That makes it extremely important to freeze potential sources of financing.

What data have you used for your work?

I was interpreting anything relevant from official sources that I could get my hands on, such as the speeches of Abu Bakr al-Baghdadi and Abu Mohamed al-Adnani, the two top ISIS figures. They are like managers, pursuing their goals rigorously. And soon I understood that it wasn't just religious fanatics and loonies following them.

But...?

Those Europeans following ISIS, are, above all, losers who feel excluded and have no perspective. Joining ISIS means exercising power, experiencing affiliation and strengthening one's self-esteem. There are religious goals: spiritual experiences, living and fighting for God. And there are, as we have missed to date, followers with humanitarian goals: end the war in Syria and the oppression by the Shias. These aren't just religiously fanatic bomb planters. You can find young doctors and lawyers among them. But they usually end up disillusioned and soon return home traumatized.

What does that mean for the war against ISIS?

We conducted 59 interviews with Muslim experts, but they didn't reveal much. That's because almost all of the experts were Shias. But for the development of countermeasures, the information is decisive. For example, a certain education about how ISIS really functions, and treats recruits, might avert people from becoming followers. More than that, we can try to involve disappointed homecomers to participate actively in informing the population.

Could the Paris attacks have been prevented with your findings?

I think that's always a very hard thing to say, with hindsight. A year later, you're always smarter. But in the long run, our findings help to point out possibilities for better protecting the population. If you understand the goals of ISIS, you can find ways to prevent them from getting what they want.

Can you make any conclusions for the German politicians?

For me, after what has happened in Paris, this means that now there are the resources for terror strikes in Europe, and that Germany must have become a target too. But I also see this as a point of reference for refugee policy.

Because terrorists are mixing with refugees?

No, I'm talking about decision theory. We first have to understand what goals we're pursuing as a society. And how do we get there? Under which circumstances? Are there alternatives? And then we should ask ourselves: What are the refugees' objectives with regard to their own lives in Germany? With these findings, we then are able to develop constructive measures to reach our targets. That's what we should be talking about, not about numbers. Because if we're not taking into account our society's goals concerning refugees, and what their own objectives are, current immigration policy might become an even bigger problem.