This book asks two interconnected questions: Why does Barack Obama continue to act unilaterally in military operations and why does Congress allow it? These are both timely and perennial questions, given the surprising continuation of Bush-era tactics and the seemingly endless War on Terror. In Obama at War, Ryan Hendrickson examines the framework for war powers in the Obama presidency and then presents four case studies, including the continued operations in Afghanistan, the fight against pirates off the Somali coast, military strikes in Libya, and the hunt for Joseph Kony, the infamous leader of the Lord’s Resistance Army (LRA). While the chapters on Afghanistan and Libya rehash the arguments of legislative supremacists, Hendrickson’s analysis of U.S. engagements with pirates—reaching all the way back to America’s founding—and his discussion of the military operation to eliminate the LRA make an impressive contribution to our understanding of executive–congressional relations in the realm of foreign policy.

In the first instance, there are both domestic and international aspects of the problem that Hendrickson deftly weaves together. He acknowledges that Congress passed a “permanent law” in 1823 giving presidents the power to deal with pirates unilaterally, without missing the normative point: The “notion of individual rights” has changed dramatically since that time, making the law “no longer inherently applicable” (p. 46). Domestically this should change, and since “international law governing piracy is far from clear,” there must be some collective efforts to clarify and reconcile both levels of law (p. 46). This chapter offers a treasure trove of research opportunities for those studying war powers, human rights, and international law.

In the second instance, Hendrickson provides a rare example of congressional activism. In Chapter 5, he shows that strong and sustained advocacy from nongovernmental organizations and a “perfect storm of political variables” can spur congressional activism in the foreign policy arena (p. 86). Upon reading this account, it is easy for a reader to think that the author means to show the elements that must come together to make the passive Congress more active. He dashes these hopes, however, near the end of the chapter when he writes: “Thus, again there is evidence in this case that Congress avoided political responsibility for the mission,” fearing the mission may become “politically unpopular” (p. 83).

In fact, this is a consistent theme throughout the work. In the introduction, Hendrickson claims that “Congress’s senior leaders … have often actively worked to avoid their constitutional duty to check the commander in chief” (p. 2). In Chapter 1, he continues, “Congress has accepted for the most part” unilateral presidential action (p. 9). This is also true—with rare exceptions—of congressional actions regarding drone strikes. In this instance, Congress is “rather compliant” and the leadership supports Democratic and Republican presidents alike (p. 33). They also “largely avoided constitutional responsibility for U.S. military conduct in response to piracy” and made themselves “irrelevant” by failing to assert their “war powers authority” in the case of Operation Odyssey Dawn (pp. 40, 58). This book may appear to critique Obama’s “imperialism” given the title, but it reads as a critique of Congress, especially congressional leadership.

This argument becomes transparent in the last two chapters. In the second to last, Hendrickson explores the careers of John McCain and John Kerry. Ostensibly, he seeks to analyze why two well-respected senators with foreign policy bona fides consistently support an overly broad reading of commander-in-chief powers. Hendrickson’s excellent research skills provide solid evidence of consistent abdication over long and distinguished careers. Presenting this clear theme, given the depth and breadth of the material covered in this chapter, is truly masterful. For example, in order to demonstrate McCain’s strong support for unilateral presidential action during the first Gulf war, the author finds a public statement from 1999 where he says that “Congress did a ‘model’ job … handling the situation that led up to the war” (p. 105).

The reader can, however, get the impression that Hendrickson seeks the information that supports his interpretation of the Constitution. This is clearest when he discusses several war-powers court cases. He refers to Talbot v. Seeman (5 U.S. 1) and United States v. Smith (27 Fed. Cas. 1192, 1229 C.C.N.Y.) as “correct” (p. 122). In both instances, the court presents Congress as the branch with the power to initiate almost all hostilities, not the president. Yet United States v. Curtiss-Wright Export Corporation (299 U.S. 304) contains an error because “Justice George Sutherland misinterpreted a speech made by Congressman John Marshall in 1800 to argue that the president is the ‘sole organ of the federal government in the field of international relation’” (p. 122). This editorializing leads the reader to wonder what else Hendrickson dismissed because it does not support his view (p. 122). Similarly, he cites Elbridge Gerry and James Madison, who both feared a powerful executive, especially in the realm of war (pp. 2, 8). While these are certainly legitimate court cases and preeminent Founders, Hendrickson consistently avoids seriously engagement with those who disagree with his reading of war powers and the Constitution. This leaves fundamental questions unanswered: If the Constitution does not allow presidents to act unilaterally, why have they consistently initiated hostilities without congressional approval and why does Congress let them?

In failing to address these questions, the book falls short in a significant respect. It is puzzling that Hendrickson does not attempt to answer these questions, given his extensive research showing the seeming hypocrisy of Senators Obama and Joseph Biden once they became president and vice president; they switched their view on congressional oversight after switching branches. What is more baffling is the actions of McCain and Kerry, neither of whom became president and both of whom support a broad interpretation of commander-in-chief powers. This remained true even after their unsuccessful presidential bids. Hendrickson gets close to answers in the chapter on Libya when discussing efforts to quash legislation associated with the operation. He writes: “Congress and its leaders excel in finding ways to avoid taking political and constitutional responsibility for the use of force abroad” (p. 69). He presents this same view in the chapter on Kony, saying that “Congress avoided political responsibility for the mission [in case] the president’s actions became politically unpopular” (p. 83).

If this is the case, why does Hendrickson fail to examine the political aspect of their decisions? Clearly, his understanding of constitutional responsibilities and constraints do not constrain presidents. Or, more implausibly, perhaps Obama, Biden, McCain, Kerry and the congressional leadership have the wrong interpretation of the Constitution. If this is true, it seems hopeless to attempt to convince them now. Given the serious nature of the problem and the very real possibility that presidents will abuse power if Congress shirks its duties, it is important to find answers. Hendrickson has done some important work demonstrating that the problem has old roots in both branches and shows no sign of changing. Without answering the deeper questions, however, Obama at War simply provides a detailed examination of undisputed facts: Presidents act unilaterally and Congress avoids responsibility.