I know I'm not the first to ask this, but exactly what theory of military action allows President Obama to do this without congressional approval? In Afghanistan and Nicaragua in the 80s, you could argue that we were merely funding allies, not fighting a war ourselves. In Grenada and Panama, you could argue that we were merely pursuing small-scale police actions. In Pakistan, you can argue that our operations are all part of the Afghanistan war. You might not like any of those arguments, but at least they're something.
But what's the theory here? This is obviously not a short-term operation (it began well over a year ago). It's obviously not part of the Afghanistan war. You'd have to twist yourself into a pretzel to pretend that the post-9/11 AUMF applies here. (The fact that Congress is considering an extension of the 2001 AUMF in order to cover operations like this is a tacit admission that the old AUMF doesn't apply.) Nor does the fact that Yemen's president has given it his blessing really mean anything from a war powers standpoint.
I say this is an odd question because while AQAP didn't exist prior to 9/11, the view that the AUMF covers military strikes on groups associated with al Qaeda that didn't play a direct role in the 9/11 attacks has been the interpretation of the AUMF the administration has relied on since it took office. That's part of the reason why it threatened to veto a more expanded version of the AUMF contained in the recent defense appropriations bill, that arguably would have put operations in Yemen on firmer legal ground. But this has been the administration's line for years, it's not anything new.
For that reason, I find Andrew Sullivan's contention that "Obama is now engaged in two illegal wars - in Libya and in Yemen," particularly odd. Sullivan defended the administration's authority to target radical cleric and American citizen Anwar al-Awlaki, but those strikes were being undertaken by JSOC under authority claimed under the AUMF. It doesn't make sense to argue that when the military was targeting him, it was legal, but the CIA's increased involvement makes U.S. operations in Yemen an "illegal war." If JSOC can legally target al-Awlaki, then there's little legal basis to argue that the CIA can't. If, on the other hand, you believe that operations in Yemen represent an expansion of the "war on terror" that isn't authorized by the AUMF, then the CIA's involvement is legally troublesome. But at the time Sullivan wrote that "Yemen surely is a "declared battlefield" - at least as far as al Qaeda is concerned." As far as the administration and most of Congress seem to be concerned too.
"If JSOC can do it, either because of the AUMF or Article II self-defense authority, then there's no reason the CIA can't invoke that same authority," Robert Chesney, a professor at the University of Texas School of Law and an expert on national security law. "The more interesting question is if you begin from the premise that the military can't do it, could the CIA then do it just because it's being done covertly?"
I'm not bringing up the al-Awlaki issue just to tweak Sullivan--the context in which this broad authority under the AUMF was most recently challenged was in the ACLU/CCR case opposing the administration's targeted killing program. The judge in that case decided that this was a "nonjusticiable" question--but this is another reason why that case was about more than just al-Awlaki's citizenship. It was also about the "global battlefield" in the fight against al Qaeda.
Ironically, the CIA's increased involvement in Yemen means more oversight from Congress; the law is very specific about covert action by the CIA and the required congressional oversight. But covert action undertaken by JSOC has taken place without such oversight. That I think, represents a very large hole in terms of accountability for actions taken in the war on terror.
The administration has said that a new AUMF merits more debate, and has threatened to veto the defense funding bill over its inclusion. I agree strongly--in part because I don't think that the original AUMF's authority extends to attacking a group that didn't exist on 9/11. But the CIA's reported escalation of drone strikes brings to mind more a policy problem than a legal one--to what extent is our singular focus on AQAP undermining our long term interests and security--since the legal one already existed.