paul salom is vice president for policy and research at the middle east institute. >> yemen descended into, you know, a failed state situation, and pretty much in all senses of the word. and an open civil war, which has its internal dynamics, but sadly has external proxy support. >> the external proxies include saudi arabia's visible military intervention on the side of the ousted government. and on the other side, iran's widely reported support for the houthis. something that tehran still denies. speaking last night on pbs's newshour, john kerry warned the u.s. will not tolerate iran's greater involvement. >> we are well aware of the support iran gives yemen. iran needs to recognise that the united states will not stand by while the region is destabilized or why people engage in overt warfare across the lines, international boundaries and other countries. >> saudi arabia military response has been to assemble a coalition of powerful arab states, including morocco, egypt, and the united arab emirates, to attack houthi positions, beginning an aerial bombing without warning. it's not ju