Shields of the Republic: The Triumph and Peril of America's Alliances.

• Author: Marston, Hunter

Shields of the Republic: The Triumph and Peril of America's Alliances. By Mira Rapp-Hooper. Cambridge, Massachusetts: Harvard University Press, 2020. Hardcover: 272pp.

The debate over Donald Trump's foreign policy legacy may not be settled for decades to come, but it is hard to dismiss the notion that few presidents in American history have been as openly critical of Washington's global network of alliances--or done as much to refocus public and academic discussion about the role of alliances in US national security strategy--as President Trump.

Taking aim at Trump's anti-alliance rhetoric and policies while casting a wider aperture in her analysis of America's history of alliances, Mira Rapp-Hooper reveals how alliances have always been controversial, poorly understood and politicized, with the burden-sharing debate that Trump has reignited being far from new (p. 78). Rapp-Hooper argues that everyday voters and scholars each bear some of the blame for the general scepticism surrounding alliances (pp. 2-3). She sets out to correct the anti-alliance narrative by identifying the ultimate value of alliances in preventing the emergence of rival spheres of influence that she asserts will take hold in places where and if the US alliance system erodes. To buttress her argument, Rapp-Hooper presents a scrupulous cost-benefit analysis of America's alliances. Drawing on counterfactuals, she demonstrates that alliances have rarely backfired on US national security policymakers and are indeed cheaper than the alternative of ad-hoc decision-making.

Coursing through the book is the tension between the utility which Rapp-Hooper ascribes to America's alliances and the simultaneous need for their renewal or revitalization. For instance, while RappHooper recognizes that Washington has retained and repurposed its alliances since the end of the Cold War, she also argues that policymakers today need a new alliance logic (p. 5). Additionally, she maintains that alliances are invaluable for US national security, yet are inadequate to meet the contemporary challenges of revanchist threats from a rising China and a declining Russia (p. 12). Ultimately this tension is somewhat unresolved, but readers will likely find Rapp-Hooper's defence of alliances' utility persuasive, even if they need updating to meet the circumstances of the twenty-first century. American alliances may have been rudderless and lacking in purpose without a clear enemy since the end of the Cold...