A couple of notes to follow up on Steve’s post [with UPDATES through Monday morning]:

Abu Anas al-Liby is alleged to have been a leader in the al Qaeda conspiracy to bomb the U.S. embassies in Dar es Salaam and Nairobi on August 7, 1998.  Assuming he has not since abandoned his role in al Qaeda, then, he is almost certainly covered by the AUMF.  [UPDATE:  The Administration apparently is now asserting AUMF authority, and a source has told the Post that al-Liby “was believed to be pivotal to the resurgence of al-Qaeda’s North Africa branch.”]  Moreover, even if he weren’t, the FBI likely had the statutory authority under 18 U.S.C. 3052 to capture him overseas in order to bring him back to the U.S. for trial (he was indicted in 2000), at least if (as the Times story suggests) the capture was done with the cooperation of Libyan authorities.  And I imagine U.S. military forces might have similar general, underlying authority to aid in such a law-enforcement capture, although I haven’t looked into that question.

What about the al-Shabaab leader who was the target of the operation in Somalia?  [UPDATE:  Latest reports are that he is a Kenyan of Somali origin known as Ikrimah, one of al-Shabaab’s “top planners for attacks beyond its base in Somalia.”]  (The operation apparently was also designed to capture Ikrimah, and reportedly was abandoned when there became a risk of civilian casualties.)  The President has already reported that “[i]n a limited number of cases, the U.S. military has taken direct action in Somalia against members of al-Qa’ida, including those who are also members of al-Shabaab, who are engaged in efforts to carry out terrorist attacks against the United States and our interests.”  Perhaps Ikrimah meets that description, in which case he would also be covered by the AUMF.   [UPDATE:  Ryan explains that that may well be the case.]  There’s also a chance that other statutory authorities would likewise have justified an operation to capture the individual in order to bring him to trial, as with al-Liby.  [UPDATE: According to the Post, “U.S. officials said both operations were lawful under war powers that Congress granted the executive branch after the Sept. 11, 2001, terrorism attacks.”]

It may well be, then, that neither of these is much of a test case, nor involves any assertion or exercise of new or expanded legal authority.

UPDATE:  Deborah Pearlstein questions whether the AUMF authorizes an attack on al-Shaabab.  But that general question — i.e., whether and under what circumstances the AUMF authorizes the use of force against al-Shabbab as such — would not need to be reached if the target here, as in the past cases about which the President has reported, was also a member of al Qaeda.

Bobby Chesney, on the other hand, suggests that perhaps the Administration was not relying upon AUMF authority in Somalia, but instead upon “Article II authority in order to prevent regional destabilization and perhaps also in the name of collective defense of various governments in the area.”  He writes that “the Baraawe raid, as currently being described in the media, does not depend on that [AUMF] model.”

Perhaps.  But that would be an expansion of justification for article II authority well beyond anything this or any other President (other than perhaps Truman and Bush 43) has previously relied.  To be sure, any threat of future attacks in Africa from the target in question would have destabilized the region in some sense–but to a far lesser degree than the threat to regional stability presented by Qhadafi’s attacks on civilians in Libya in 2011, a threat that OLC deemed only relevant, not constitutionally sufficient, to justify unilateral presidential action there.  (If the Somali government, such as it is, invited the U.S. to strike where the Somalis themselves could not, that fact might be relevant, if not sufficient, on the question of whether the President could act unilaterally–see the OLC opinion on the 1994 U.S. operation in Haiti.  But I have not yet seen any information about possible Somali invitation or consent.)

Therefore, I think it is far more likely that the justification for the Somali operation is that it was statutorily authorized under the AUMF, or under some other authority to render a suspect to criminal prosecution.  [UPDATE: According to the Post, “U.S. officials said both operations were lawful under war powers that Congress granted the executive branch after the Sept. 11, 2001, terrorism attacks.”]

Finally, Deborah wonders whether the capture of al-Liby violated international law.  I assume she means customary international law, which was at issue when, for instance, Israel captured Adolph Eichmann in Buenos Aries in 1960, and when the U.S. helped to abduct Humberto Alvarez-Machain from Mexico in 1990.  (In both cases, the individual was captured in order to bring him to trial–just as al-Liby presumably will be.)  She’s right that the international law question is a very serious one in such cases, where the first resort is supposed to be asking the host state to detain and extradite the suspect.  (Abduction might be justifiable where the host state is unable or unwilling to do so; but that’s a complicated and deeply contested question.)  The legal question does not even arise, however, if the host nation consents to the abduction.  Here, Libya’s interim government is now demanding an explanation from the U.S. for what it is calling the “kidnapping” of al-Liby.  Unnamed American officials, on the other hand, told the New York Times that “the Libyan authorities, in a shift, were willing to tacitly support the raid as long as they could protest in public.”  Unless and until we know, at a minimum, whether Libya consented to the operation, it will be difficult to assess whether that rendition to trial violated international law.