There has been surprisingly little discussion about the international legal justification for the airstrikes in Yemen that are being led by the Saudis. Other than a Just Security post that tackles some of the legal issues, the media and those using force have spent almost no time discussing whether the Saudi-led coalition's intervention raises legal questions. That in itself is notable. States seem to be making fewer efforts these days to discuss their international justifications for using force (with a few exceptions), and few other states are demanding clear explanations for the force. (Consider, for example, the airstrikes by Egypt and the UAE in Libya in August 2014, which both states refused to discuss.) This could become an even more salient problem if the regional military force that the Arab League is discussing takes shape. The existence of such a force increases the likelihood that we will see military interventions by states that do not seem committed to articulating legal justifications.

Ashley S. Deeks, International Legal Justification for the Yemen Intervention: Blink and Miss It, Lawfare (March 30, 2015).