A previous version of the UN resolution stumbled Thursday because Russia wanted groups it says are allied with terrorists to be excluded from the ceasefire. Some of those groups are active in Eastern Ghouta, meaning that if Russia’s demands were met, the resolution would have allowed Assad to keep pummeling the area. It is immediately unclear whether the resolution that was unanimously approved Saturday accommodated Moscow in this way. If so, it will do nothing to stop the ongoing slaughter.

Nauert said Russia bore “a unique responsibility for what is taking place” in Eastern Ghouta, and she was right. “Without Russia backing Syria, the devastation and the deaths would certainly not be occurring,” she said. But when pressed about what more the U.S. could be doing diplomatically in Syria to stop the violence, she replied: “I don’t know what some of you expect us to do. … Our best tool … is an attempt at diplomacy. … We will continue to do that.”

Humanitarian groups describe a desperate situation in the region. Water, food, and fuel are in short supply. Civilians are digging underground shelters in order to escape the daily bombardment. There are no routes to medically evacuate the sick or dying.

The U.S. has troops in Syria to fight ISIS, but there’s still no envoy for Syria in charge of diplomacy. The U.S. is the largest humanitarian aid donor in Syria, but the Syrian government has blocked the delivery of supplies in rebel-held areas. “What we’re seeing ... is some of the worst violence we’ve seen in more than seven years,” said Dafna Rand, the vice president of policy and research at MercyCorps. The humanitarian group has been active in Syria since the start of the conflict in 2011. “We are having a hard time reaching people because our partners (on the ground)—their lives are endangered by the violence. … Our staff are risking their lives every time they go outside to distribute anything.”

Assad’s past use of chemical weapons on his own people gets much of the publicity—a sarin gas attack in Eastern Ghouta, the very same area currently under bombardment, nearly led the Obama administration to intervene against Assad in 2013—but conventional weapons are killing a much higher number of people. MercyCorps, in a new report, said the Syrian conflict “has spiraled into a humanitarian crisis unprecedented for our modern times.” About 400,000 Syrians have been killed and 11 million others have been displaced—about half of them now live in refugee camps outside the country.

The conflict also shows the limits of international diplomacy. There are two dueling international peace processes, neither of which has produced much in the way of peace. The Astana process, which was overseen by Russia, Iran, and Turkey, established “de-escalation zones” where the fighting would stop to facilitate peace talks between Assad’s government and the rebels. Eastern Ghouta is supposed to be one of them. “So much for that de-escalation zone,” Nauert said Thursday. She said Russia “can get back to trying to create a de-escalation zone, but we want them to get back to the Geneva process.”