This post is excerpted with the permission of carnedgieendowment.org.

In practice, most of these agreements are hard to distinguish from capitulations by rebels embedded in a civilian community that has been exhausted by war and starvation. “People have limits, and we reached ours,” a rebel commander from Moadhamiya recently told the Wall Street Journal’s Sam Dagher. “We were ready to cling on to anything to get food for us and the children.”

In other words, hunger has worked as intended. Several Damascus suburbs have now been brought to their knees. While the truces remain shaky, this still-expanding process represents one of the most significant government advances during the entire war. It is extremely unlikely that the regime will voluntarily give up such an effective tool, particularly as it is now slowly closing in on new areas, like the Rastan pocket north of Homs—and perhaps in the future even eastern Aleppo.

On the rebel side, the situation is more complex, given the divisions among the hundreds of rebel groups. Exile politicians attuned to international sensitivities will breezily condemn such sieges even as their rebel allies implement them on the ground. But regardless of contradictory rhetoric and weak strategic consistency, the consequences for the civilians under siege in Nubl and Zahraa are just as disastrous.

Imposing starvation on civilian populations is a war crime, yet like most war crimes it is also very effective. UN Resolution 2139 has brought attention to this cruel aspect of Syria’s war and increased the involvement of the Security Council, but unless the international community is somehow able to change the calculus for both Assad and his enemies, Syrians will continue to die from hunger.