ISIS has made alarming gains in Iraq and Syria over the past week.
On May 17, ISIS fighters took Ramadi, a city just 70 west of Baghdad, after a battle in which the jihadist group advanced into the city behind a wave of suicide bombers. Capturing Palmyra, a former Assad regime bastion in Syria, proved easier, as a collapsing Syrian military essentially vacated the city in the face of the ISIS advance.
And an 11-month US-led bombing campaign hasn't prevented ISIS from taking and holding additional territory. This week, ISIS has looked formidable, while the US's strategy has seemed particularly ineffective and aimless. On May 21st, reports began circulating that ISIS controlled half of Syrian territory.
But such claims about ISIS's degree of territorial control obscures how and why the group has been successful so far — and how it might eventually be defeated. ISIS doesn't really "control" half of Syria.
As these maps from the Institute for the Study of War demonstrates, ISIS has a sliver-shaped core of direct administrative control, insulated by hundreds of square miles of desert where the jihadist group and other militant forces maintain a degree of operational capability.
There are gradients of ISIS control in Syria, and understanding them hints at how the group can be successfully countered.
"ISIS's fighters are likely clustered in key defensible terrain," Jennifer Cafarella, a Syria conflict analyst at the Institute for the Study of War, told Business Insider. Cafarella explained that ISIS focuses its efforts and manpower around the populated and strategic areas along the Euphrates river.
"There's little actual human terrain in close proximity to ISIS in eastern Syria that ISIS does not already control," she said. "Beyond that is the vast Homs Desert, where ISIS has been able to operate with impunity.
"But it's too inhospitable for any military to decisively hold and of low enough strategic value that is can't be considered an exclusively ISIS-governed area."
As Cafarella says, the desert in the east of the country is at least "maneuverable terrain by really all military forces."
The issue is that ISIS currently has free reign there — the Assad regime, for instance, doesn't have the on hte ground intelligence, the capacity, of perhaps the willingness to discover and then bomb ISIS convoys traveling across Syria's desert east.
"We still don't have the ground partner necessary to contest ISIS-held terrain inside of Syria in any meaningful sense," says Cafarella.
In Syria, ISIS has a small core area of control, a wider area of operational freedom, and no real ground-level counter-force pressuring the group.
What it doesn't have is an administrative entity that actually comprises half of the country's territory.
In other areas, over-emphasis on ISIS's territorial control can have an even more distorting impact on the group's actual reach. In Libya, it's been frequently reported that ISIS rules over territory, with The New York Times reporting in March that ISIS had a foothold in Sirte, along the Mediterranean coast. On May 21st, Reuters reported that ISIS had captured the city.
In reality, ISIS doesn't really control any territory in Libya, or at least not in the same sense as in Iraq and Syria.
"The places they're said to be in control of are heavily contested," Daveed Gartenstein-Ross, a senior fellow at the Foundation for Defense of Democracies, told Business Insider. "It hasn't captured cities and imposed an administrative structure."
The idea that ISIS has territorial control in Libya "directly feeds into ISIS propaganda," says Gartenstein-Ross. It shows that the "caliphate" has spread beyond Iraq and Syria, and that he group can fight and hold territory far beyond its center of power. An exaggerated sense of ISIS's Libya capabilities may have been part of what convinced the Nigerian jihadist group Boko Haram to pledge allegiance to ISIS in March.
Understanding the nature and extent of ISIS's territorial control is especially important amidst growing criticism of the US's strategy against the group. Gartentstein-Ross explained that ISIS has adjusted its own battlefield approach, opting for small-scale attacks over vulnerable large-scale mobilizations. Furthermore, the group is only opening fronts against forces they are relatively certain they can defeat, like the Iraqi military.
"They're using smaller and more mobile units that are better at evading the air campaign," says Gartenstein-Ross.
ISIS's tactics are adjusting to the US's now 11-month-old air campaign, but this doesn't mean the group is invincible. ISIS took Palmyra because the Syrian regime fled, and it took Ramadi because the Iraqi Security Forces aren't a viable or a competent fighting force.
On the other hand, ISIS has an apparent unwillingness to contest areas held by battle-hardened Iranian-supported Shi'ite militia groups in both Iraq and Syria, and has made little progress against Kurdish forces in either country.
So even as the group expands, it's clear that it isn't on an inevitable victory march across Iraq and Syria.
"I don't think their capability should be overstated vis a vis the full range of their opponents," says Gartenstein-Ross.
