'A hospital associated with Doctors Without Borders. A school. A potato chip factory. Under international law, those facilities in Yemen are not legitimate military targets. Yet all were bombed in recent days by warplanes belonging to a coalition led by Saudi Arabia, killing more than 40 civilians. The United States is complicit in this carnage. It has enabled the coalition in many ways, including selling arms to the Saudis to mollify them after the nuclear deal with Iran. Congress should put the arms sales on hold and President Obama should quietly inform Riyadh that the United States will withdraw crucial assistance if the Saudis do not stop targeting civilians and agree to negotiate peace.'