Hundreds of thousands of people have died in Syria's civil war since it began almost four years ago — and there's no end in sight. Bashar al-Assad's regime has been unable to destroy ISIS, Jabhat al-Nusra, or the anti-government rebels. And the rebels have been unable to decisively defeat Assad. It's a bloody stalemate — and here are two statistics about the war that will help give you a sense of how that stalemate works.

Fabrice Blanchard, a French academic who studies political control of territory in Syria, talked to the Carnegie Endowment's Aron Lund about the state of the conflict. His estimates of the territory and population controlled by the Assad regime are particularly striking.

The Syrian government currently controls around 50 percent of the territory, but it rules between 55 and 72 percent of the population left inside Syria. The rebels control 45 percent of the territory and 17-34 percent of the population, while the Kurds control no more than 5 percent of the territory with 5-10 percent of the population.

So, on the one hand, the Syrian government only controls about half of its territory — not exactly the sign of a strong government crushing rebel forces.

But Blanchard thinks you shouldn't focus just on this number. Territorial control "doesn't give a good understanding of military realities," he says, "because a vast rural area is less strategically relevant than the major cities or the principal axes of communication." The fact that the regime controls a proportionally higher percentage of people than land — between 55 and 72 percent of the Syrian population is under government control — indicates that it's stronger in a number of strategically important areas. Look at the red on this map, indicating areas of government control: it's not a lot of the country, but it includes much of its western population centers and ports.

However, Assad forces aren't so strong as to be able to kick rebels out of all populated areas, given that the government may rule over as little as 55 percent of the population. You've got a situation where no one military faction is clearly dominant — and the Syrian people, caught in the crossfire, pay the price for their unending warfare.

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