As was reported in the New York Times and elsewhere on May 2, the U.S. fired at least four Tomahawk cruise missiles into Somalia, striking a compound in the town of Dusa Marreb, killing at least ten people. 
One of them, the primary target of the attack, was an alleged Al Qaeda operative named Aden Hashi Ayro, who was suspected of having killed a BBC journalist among other things. He was reported to be a notorious terrorist.
Several blog posts have noted the lack of mainstream discussion on the legality of this missile strike. Prof. Marty Lederman, writing in Slate, suggested that few seem to care whether it was legal. But even among the bloggers, the majority of posts I have seen, as in the case of Prof. Lederman’s, have focused primarily on the constitutional issues of whether the President had sufficient authority, explicit or otherwise, to launch such attacks. There has been some discussion of the jus in bello issues, such as whether the strikes met the criteria of military necessity and proportionality, given the apparent collateral damage. But few have addressed the jus ad bellum issues – was this missile strike, and those prior to it (there have been several such attacks on Somalia since 2006) lawful under the international laws on the use of armed force?
Developments in jus ad bellum?
Prof. Jullian Ku was one of few that has raised the issue, on Opinio Juris, but he merely floated the idea that since such strikes have met with little objection, they may be evidence that the U.S. is operating in a legal paradigm that approximates that of war. Implicit in this is the proposition that there have been developments in international law on the use of force since 9/11 that permit one to wage war on organizations, and which give the global “war on terror” a legal foundation that would permit such strikes against Al Qaeda operatives at large in a “failed state”.
As I commented on his post over at Opinio Juris, I question whether the fact that there has been little formal objection to the strike can be said to support the inference that the strikes were therefore lawful or justifiable under international law, or that it reflects developments in international law that permit such strikes.