In the U.S. system of “checks and balances,” conflicts are common between the executive, legislative, and judicial branches of government, particularly when the decisions of one directly impact the policies or authorities of another. These conflicts take center stage in Gregory Burnep's book Courts at War, which traces the contested evolution of two specific policy areas since 2001—detention of terrorists and military commissions—from the perspective of the judicial branch, where “lawsuits and court rulings have repeatedly generated significant policy changes” (p. 158).

Myriad case studies are presented in considerable detail to illustrate what the author sometimes calls “entrepreneurial lawyering” or (paraphrasing Robert Kagan's work) “legal adversarialism.” For example, Burnep describes how “a steady drumbeat of lawsuits and court rulings contributed to the enactment of significant policy reforms and the release of scores of Guantanamo detainees” (p. 64). Further, as a result of its contested evolution, “detention policy has become highly insulated from direct presidential control” (p. 68). This is why President Barack Obama was ultimately unable to achieve his campaign promise to close Guantánamo Bay, and why President Donald Trump was unable to achiev