The Islamic State of Iraq and Syria militant group has occupied a huge swath of northwestern Iraq and, it claims, executed more than a thousand Iraqi army troops its fighters captured.

ISIS says it wants to establish an Islamic caliphate in what is now Syria and Iraq. In the following op-ed, Franz Gayl, a U.S. Marine Corps science adviser, argues that maybe the world should let that happen.

We’ll offer a rebuttal of Gayl’s idea on June 17.

When civilized peoples confront savagery—like that of the Islamic State in Iraq and Syria today—they’re always at an initial disadvantage, always surprised. Who expects barbarians in the modern day?

Moreover, the militants embed themselves in rational states. They blend in until they strike. They surround themselves with innocent civilians as human shields.

They make themselves hard for us to attack.

Nevertheless, we can still turn the tables on ISIS. In this, a geographically-defined extreme caliphate—which ISIS claims is its goal—may be just what we need.

It would greatly simplify our targeting challenge.

The non-state status of terrorists and militants has generally been problematic. They are nowhere and everywhere. So we end up fighting messy counterinsurgencies and a long war on terrorism. We also accept debilitating restrictions on where and how we can attack.

We have seen political fanatics like ISIS before. These extremists are merely new manifestations of Nazi and Japanese imperialists—who are essentially their psychological analogs. The common hallmark of these thug ideologies? Arrogance.

They can’t imagine that the very thing they want … is also their greatest weakness.

Our major disadvantage today is that our enemy lacks a geographical home. This has prevented us from targeting these barbarians and their sympathetic and supportive families and communities.

A new caliphate would mitigate this disadvantage. A hardline Islamic state would reflect the basic characteristics of Nazi Germany or Imperial Japan, which we managed to defeat by conventional means.

It would include cities and villages that we can identify on a map. It would have infrastructure that we can easily destroy. It will also feature ideological purity, helping to ease the moral dilemma of our own massive attack on the state. Everyone in the caliphate would be a combatant or the combatants’ direct supporter.

Our enemy would be concentrated … and eminently bomb-able.

Extremists in this century deserve no more humane consideration than did the radicalized German and Japanese empires of the last one. Our demand for unconditional surrender then meant the enemy had to submit or die.

Our strategy was effective. The world is better off for it.

The cancer of extremism threatens most modern states—Russia, China, most Arab countries … nearly everyone. Whatever our differences, we all are civilized and rational states facing an existential threat.

And I must point out that the militants’ sadistic bloodlust has nothing to do with Islam. Such attitudes and behavior are the antithesis of Islam and all other revealed scripture.

The Sunni-Shia rift occurred after the Prophet Muhammad’s death—and he would have condemned indiscriminate cruelty like ISIS’ as arrogance and disbelief. He would have turned his face from such self-idolizing hypocrites, frauds who reject true belief as they come to see themselves as god-like.

So let’s accept the extremists’ desire for a caliphate. It’s for just such geographically-concentrated, unrelenting and un-reformable aggressors that we developed strategic air power.

Let them have a caliphate. And then let’s bomb it.