Children were the first victims of the Syrian regime's crackdown that began in March 2011. In the city of Daraa, schoolchildren were detained and tortured for scrawling graffiti expressing opposition to President Bashar al-Assad.

By February 2012, Syrian forces had killed 500 children, according to Navi Pillay, the UN human rights chief. "They've gone for the children -- for whatever purposes -- in large numbers," Pillay told the UN Human Rights Council, as she appealed once again for the UN Security Council to refer Assad to the International Criminal Court for crimes against humanity.

Last weekend's massacre of at least 49 children among the more than 120 killed in Houla was part of the same pattern of targeting youngsters that has been central to Assad's murderous response to any dissent from his rule. The coordinated decision of Australia, Canada, France, Germany, Italy, Spain and the United States to expel Syrian diplomats expresses their genuine revulsion at the Houla massacre and Assad's adamant denial of responsibility, but such punitive diplomacy is not enough.

World powers have wrestled, to no avail, with the task of identifying and implementing the best course of action to turn off the Assad regime's killing machine. More than 10,000 are dead, countless others imprisoned and tortured, and there is no end to the carnage in sight.

If Assad possesses any ounce of humanity in his heart or mind, the U.S., European Union, UN, Arab League and Turkey, among others, have not been able to pinpoint it. In word and deed, Assad has consistently refused to discuss with anyone, in sincerity, an end to Syria's internal conflict.

The ferocity of the Assad regime's assault has only intensified since former UN Secretary General Kofi Annan claimed that Assad had accepted his six-point cease-fire plan. The plan, endorsed by the UN Security Council, authorized the dispatch of 300 international monitors to supervise implementation of the cease-fire.

Had Assad truly been committed to the cease-fire, he would have implemented the first of the Annan plan's six points by withdrawing his forces from Syrian cities and stopping the killings before any UN monitors arrived. Tragically for the Syrian people -- and now especially for the slain children in Houla -- the UN presence has helped legitimize Assad's continued rule by force. Since the UN monitors arrived, Assad held questionable parliamentary elections and stepped up the violent crackdown, while continuing to receive support from Iran and arms shipments from Russia.

The UN should admit failure, remove the powerless international monitors, and regroup to devise a new approach. What is needed now, first and foremost, is concerted, stepped-up pressure on Russia, as well as on China, to stop defending Assad. They should end all support for the regime, stop blocking meaningful UN Security Council resolutions, and join in the international sanctions. And last summer's call by the U.S., European Union, and other nations on Assad to step down must be forcefully reasserted.

Images of small bodies wrapped in white sheets laid to rest in mass graves in Houla, and of playful Syrian children still fortunate to be alive, should move any genuinely caring world leader. Assad's removal is essential to saving Syria's children and achieving peace in the country.

Kenneth Bandler is the American Jewish Committee’s director of media relations