Imagine a war raging in central Texas, stretching eastward. San Antonio lies in the southwest of our fictional battlefield, Austin is 80 miles to the north, and Dallas sits 200 miles farther along the same highway, near the northwestern border. Houston does not exist as part of the conflict, lying just outside the southeastern border, and the northeastern edge of this war-torn country peeks into Louisiana and Mississippi.
During this devastating conflict, many areas have fallen outside the government's control. Rebel groups have seized huge swaths of territory starting a few miles east of Dallas and progressing all the way to our country's eastern border. The rebels hold sway over dozens of towns, from Greenville, Texas (population: 25,557), all the way to their de facto capital in Shreveport, Louisiana (population: 200,327). With insurgents also seizing many villages to the west and south of Dallas, the government has lost control of roughly 75 percent of the country's territory.
Most Americans would understand intuitively how to win this war. The key is to capture the cities spread across the country's western spine: The metropolitan areas of San Antonio, Austin, and Dallas are home to over 10 million people, dwarfing the villages in east Texas and the scrub brush hinterlands of the Deep South. Control those three cities, and you can muster the resources to beat back a rural insurgency - or hold enough leverage to negotiate an end to the conflict on your terms.
President Bashar al-Assad has grasped this strategy and is using it to thwart those who seek to topple him. Our fictional battlefield is, of course, a map of Syria grafted onto an American landscape: San Antonio lies roughly where Damascus would be, Austin stands in for Homs, and Dallas is Aleppo - the three largest, most prosperous Syrian cities before the war. The war has particularly devastated Homs and Aleppo, with many of the cities' residents fleeing abroad or to government-held areas around the capital or the coastal districts. But these urban centers still remain vital to Syria - and Assad has made significant progress in securing them, as his opponents squabble among themselves on the country's fringes.