Senator Leahy’s questioning about executive authority — like much of the public debate over executive authority — seems ungrounded in any longstanding understanding of executive power. I believe it is incontrovertible that some element of the President’s authority as Commander-in-Chief is beyond direct Congressional control. The key issue is whether a given exercise of executive authority — whether surveillance, detention, troop deployment, or something else — lies within that core of inherent authority. As Justice Jackson’s Youngstown Steel opinion made clear, the President’s authority is at it lowest ebb when the President acts contrary to a Congressional enactment, but it is not reduced to zero. For instance, I think most would agree that Congress could not use legislation to direct tactical troop movements in the course of a military campaign. Not only would this be impractical, but it would be an unconstitutional infringement on Presidential power. This does not mean the President is “above the law.” Rather, it means that the law — as embodied in the Constitution — recognizes that not all executive authority is subject to Congressional constraint. Judge Alito is unlikely to say this directly — as his Senate questioners would not like to hear that their power is limited — but that does not make it any less so.