We Now Have A Much Better Idea Of How The ISIS 'Caliphate' Operates

ISIS blitzed through Iraq and Syria over the summer, seizing Iraq's second-largest city, ethnically cleansing entire minority groups, and executing US and British hostages.

At times, the group appeared to have a less-than strategic approach to holding its suddenly Belgium-sized domain, baiting a US-led coalition into airstrikes and opening fronts against the Syrian, Iraqi, and Kurdish militaries.

But as a new report from Charles Lister of the Brookings Institution's Doha Center demonstrates, there's one big reason the group has managed to hold out against a diverse roster of enemies while securing and even deepening its rule.

ISIS has claimed the mantle of statehood, declaring itself a "Caliphate" and changing its official name to simply the Islamic State. Through a combination of over-the-top cruelty backed through less grotesque methods of institutional capacity building, they've partially delivered on this foundational and grandiose claim.

Indeed, part of what makes ISIS such a grimly pioneering organization is its connection of its jihadist legitimacy to its territorial holdings.

While Al Qaeda is a sometimes-loosely constructed transnational network committed to warfare against western targets around the world, ISIS is a rigid hierarchy associated with a single piece of land that it claims to rule in accordance with traditional Islamic principles. From this vast safe-haven, ISIS has amassed hundreds of millions of dollars and built an army of 31,000 fighters, according to Lister's report.

Lister's report suggests that ISIS's state-building project - the thing that makes the group so threatening and and in some ways so different from its predecessors - has been alarmingly successful. He recounts several, sometimes unexpected ways ways in which ISIS has turned itself into a functioning state strong enough to survive the numerous pressures it faces and deepen its claim to a "Caliphate."

Here's what he found.

ISIS is is a "tightly controlled and bureaucratic organization." ISIS operates an efficient hierarchy, beginning with Abu Bakr al-Baghdadi and a small executive-level team consisting of an advisor and one deputy each for Iraq and Syria. Below them are "an eight-man cabinet and a military council of at most 13 men."

And even further down are local military commanders, male and female religious police, tax and zakat (charity) collectors, and non-military offices that even include a consumer protection bureau in Raqqa.

As Lister explains, ISIS is a sprawling yet efficiently run organization with a fairly stable chain of command.

There are hundreds of former professional military officers in ISIS's ranks. Including a couple of very experienced ones: "Abu Ali al-Anbari, the chief of Syria operations, was a major general in the Iraqi Army and Fadl Ahmad Abdullah al-Hiyali (Abu Muslim al-Turkmani), the chief of operations in Iraq, was a lieutenant colonel in Iraqi Military Intelligence and a former officer in the Iraqi Special Forces," writers Lister.

And that's on top of as many as 1,000 "medium and top level field commanders, who all have technical, military, and security experience," according to ISIS documents found in June that Lister cites.

ISIS not only has a corps of trained officers to organize its 31,000 fighters. They're also capable of attracting and keeping individuals who fought for secular state militaries - a group which likely includes Sunnis who agree with ISIS's sectarian agenda without buying into its radical jihadist ideology.

Part of ISIS's appeal, Lister explains, lies in its ability to present itself as the purest and most legitimate expression of Sunniism in Iraq and Syria, something that widens the group's appeal beyond just hardcore jihadists.

ISIS has sophisticated force management that resembles that of a formal military. Lister explains that ISIS fighters have "appeared administratively akin to a nation-state's army, with units rotating between active frontline duty, days off in 'liberated' areas and other deployments 'on base.'"