David Dayen objects to the Obama administration's decision to send 100 American troops as part of an effort to hunt down war criminal Joseph Kony. The action, according to Dayen, "furthers a long, slow decline whereby the President becomes a unitary executive in matters of foreign policy, even though Congress has explicit rights regarding war powers." On a technical point, the "unitary executive" actually refers to a theory about the president's control of the executive branch; presumably what Dayen means is that this action will further the unilateral power of the president in military affairs.
But does it? Via my colleague Robert Farley, Tom Hilton cites the relevant portion of the LRA Disarmament & Northern Uganda Recovery Act. Congress, in fact, unambiguously authorized the Obama administration's actions against the Lord's Resistance Army:
...providing political, economic, military, and intelligence support for viable multilateral efforts to protect civilians from the Lord’s Resistance Army, to apprehend or remove Joseph Kony and his top commanders from the battlefield in the continued absence of a negotiated solution, and to disarm and demobilize the remaining Lord’s Resistance Army fighters
According to Dayen, this is inadequate for two reasons. The first is that it doesn't include a formal declaration of war. But going back to the Jefferson administration, it has never been the case that every deployment of military force required a declaration of war. Second, he argues that he's "not sure" that this is what sponsors like Human Rights Watch and Russ Feingold "had in mind." Leaving aside the fact that Dayen provides no evidence that HRW or Feingold didn't intend to permit military action against the LRA -- an implication that seems to contradict the explicit statements of HRW -- the executive branch is bound by the statute Congress enacted, not by what individual members of Congress or human-rights organization subjectively hoped to achieve. And this statute clearly authorizes the actions Obama took.
I take no position on whether the Obama administration's actions are prudent or likely to be effective. But in terms of constitutional restrictions on executive power, the actions against the LRA are completely unobjectionable. Unlike Libya, this was done right, with the ex ante authorization of Congress.