When the United States goes to war, the nation’s attention focuses on the president. As commander in chief, a president reaches the zenith of power, while Congress is supposedly shunted to the sidelines once troops have been deployed abroad. Because of Congress’s repeated failure to exercise its legislative powers to rein in presidents, many have proclaimed its irrelevance in military matters.

After the Rubicon challenges this conventional wisdom by illuminating the diverse ways in which legislators influence the conduct of military affairs. Douglas L. Kriner reveals that even in politically sensitive wartime environments, individual members of Congress frequently propose legislation, hold investigative hearings, and engage in national policy debates in the public sphere. These actions influence the president’s strategic decisions as he weighs the political costs of pursuing his preferred military course.

Marshalling a wealth of quantitative and historical evidence, Kriner expertly demonstrates the full extent to which Congress materially shapes the initiation, scope, and duration of major military actions and sheds new light on the timely issue of interbranch relations.

A thorough reassessment of how domestic factors do and do not constrain the use of American military force abroad in the early twenty-first century.

More than two decades have passed since the September 11th terrorist attacks resuscitated debates about the “imperial presidency” within the United States. During that same time, the United States has fought costly and inconclusive wars in Iraq and Afghanistan, pivoted to the Pacific to counter China, and pulled its gaze back to Europe and the Middle East in response to wars in Ukraine and Gaza. Moreover, new technologies and ways of funding and staffing wars have made the costs of war less visible to the public while polarization has increased and a new legal doctrine of presidential power has gained force.

Against this backdrop, Checking the Costs of War reassesses how domestic factors have both constrained and failed to constrain the use of military power across different contexts and over time. Richly empirical chapters explore the varying effects of different kinds of potential checks: legislative, public opinion, and bureaucratic. Collectively, chapters offer new insight into the prospects for war and peace today.

Throughout American history, presidents have shown a startling power to act independently of Congress and the courts. On their own initiative, presidents have taken the country to war, abolished slavery, shielded undocumented immigrants from deportation, declared a national emergency at the border, and more, leading many to decry the rise of an imperial presidency. But given the steep barriers that usually prevent Congress and the courts from formally checking unilateral power, what stops presidents from going it alone even more aggressively?  The answer, Dino P. Christenson and Douglas L. Kriner argue, lies in the power of public opinion.

With robust empirical data and compelling case studies, the authors reveal the extent to which domestic public opinion limits executive might. Presidents are emboldened to pursue their own agendas when they enjoy strong public support, and constrained when they don’t, since unilateral action risks inciting political pushback, jeopardizing future initiatives, and further eroding their political capital. Although few Americans instinctively recoil against unilateralism, Congress and the courts can sway the public’s view via their criticism of unilateral policies. Thus, other branches can still check the executive branch through political means. As long as presidents are concerned with public opinion, Christenson and Kriner contend that fears of an imperial presidency are overblown.