Throughout the history of the United States, the nation's presidents have shown a startling power to act independently of Congress and the courts. Using such tools as executive orders and memoranda, presidents have taken the country to war, abolished slavery, authorized widespread electronic surveillance, shielded undocumented immigrants from deportation, and more. As a result, executive authority has at times been accused of verging on the imperial. In this book, Dino P. Christenson and Douglas L. Kriner consider an oft-overlooked question: Given the strength of unilateral executive action and the steep barriers for Congress and the courts to successfully check it, what stops presidents from asserting control even more broadly than they already do? The answer, Christenson and Kriner argue, lies in the reactions of everyday Americans. 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 high levels of public support, and constrained when they are down in the polls, as unilateral action could jeopardize future initiatives and render presidents even more politically vulnerable. Although they find little evidence that the public instinctively recoils against the use of unilateral action, 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. On the whole, as long as presidents are concerned with public opinion, Christenson and Kriner contend that fears of an imperial presidency are overblown. However, a president who responds only to the narrow base and ignores the mass public could pose a unique threat to checks and balances.