Oh Lord, for Alliance!

American power is based on a paradox. There has never been a more prosperous and powerful country in the history of the world, but the security and prosperity of the United States depend on the cooperation and good will of allied nations. This paradox is implicit throughout Mira Rapp-Hooper’s concise and authoritative case for restoring these American alliances in her new book, Shields of the Republic: The Triumph and Peril of America’s Alliances.

The book covers Cold War and post-Cold War alliance arrangement in almost exactly equal amounts. The author weaves together international relations theory, international law, and history to explain the evolution of alliance logics over time and across regions. While Rapp-Hooper nods briefly to America’s critical alliance with France during the Revolutionary War, her analysis truly begins at the end of World War II, when U.S. leaders realized that the country’s isolationist, anti-foreign entanglement prewar stance was too risky for an increasingly globalized world.

Rapp-Hooper identifies three primary benefits that arose from our Cold War-era alliances. First, security guarantees allowed the United States to station troops abroad permanently as part of a forward-deployed military posture. Second, alliances enabled “extended deterrence:” Bringing allies under the American nuclear umbrella deterred adversaries from striking those allies and dragging the United States into war. Finally, alliances provided a way for the United States not just to assure but also sometimes to control their allies. This control was a special advantage in the Asian alliance network, where the United States sought to limit the remilitarization of Japan and prevent nationalist leaders like Taiwan’s Chiang Kai-shek and South Korea’s Syngman Rhee from entrapping the United States in their respective conflicts.

The author contrasts these tangible advantages with the more nebulous aims of the post-Cold War “unipolar” moment. Rapp-Hooper argues that without an obvious adversary, America’s alliances were neglected. While she resists the argument that NATO expansion provoked Russian aggression, she observes that the expansion lacked clear objectives. Years later, threats like North Korea and terrorism emerged to give American alliances a newfound purpose; but they could not substitute for a well-defined common enemy and, thus, left the U.S. somewhat unmoored from its longtime partners.

Finally, Rapp-Hooper turns to the present day and the challenges posed by Russia and China. U.S. alliances, she argues, have now become victims of their own success. They have successfully deterred challengers from using conventional military force to achieve their end. Instead, adversaries challenge our allies through what Rapp-Hooper terms “competitive coercion,” (often called gray zone or hybrid threats). Malign but deniable activities like cyberattacks, disinformation campaigns, and political subversion do not trigger mutual defense treaties but still undermine the security of the United States and its allies. As Beijing and Moscow have updated their strategies for the 21st century, American and allied policymakers have been caught flat-footed.

Values-Added or Values-Subtracted?

Rapp-Hooper takes a clever approach to her defense of American alliances. She directly confronts realists’ arguments for a restrained foreign policy and a reduction of U.S. commitments to its allies. In doing so, she co-opts realists’ own metrics to evaluate American alliances in strictly military and geopolitical terms. She tries to beat the “restrainers” at their own game, showing that alliances are not just the foreign policy orthodoxy of Cold War statesmen, but are tangibly beneficial. While this approach is well-suited to winning over alliance skeptics, it overlooks the intangible benefits that alliances accrue to American security.

For example, Rapp-Hooper avoids mentioning the ways in which alliances advance not only American interests but American values. Part of the great heritage of the American alliance system is the common commitment to democracy and freedom, with roots on the beaches of Normandy. While authoritarian partners, like the Soviet Union, have turned into foes, democratic allies like Great Britain, Australia, and Canada have fought with the United States in multiple conflicts since the Second World War. While the United States might share security interests with authoritarian regimes in particular situations, the U.S. maintains common interests with other democracies across generations and on a variety of issues by virtue of the similar characters of our governments and societies. Moreover, our security guarantees have also advanced democracy in allied nations, ending the Marcos regime in the Philippines and helping South Korea progress from an impoverished military dictatorship to a thriving democracy. Rapp-Hooper acknowledges, at length, the chronic skepticism that these alliances face; but they are shored up in public opinion by the fact that they protect a shared way of life. Common values enable alliances to weather crises and withstand the test of time.

Rapp-Hooper’s heavy focus on tangible interests over democratic values also risks neglecting the ideological dimension of the current geopolitical competition. The tactics associated with competitive coercion directly target fundamental attributes of free societies. The United States and its democratic allies share common interests in countering these malign activities because they share similar political systems; failing to recognize this commonality and leverage it to rally allied and public support would be strategic malpractice. Democracies in both Europe and Asia are vulnerable to not just domestic issues like strained welfare states and demographic imbalances but economic and military retaliation from authoritarian powers. Building coalitions to counter these authoritarian powers will require convincing allies to tolerate risk and contribute to collective security from their limited resources. Appealing to shared values will be a vital tool in this persuasive effort.

Paying to Play

Rapp-Hooper engages with the argument that U.S. allies free-ride on American security guarantees. Previous administrations have criticized almost every American ally for failing to contribute its fair share toward mutual security. In 2014, NATO members pledged to reach defense spending levels of 2 percent of GDP by 2024; most have not come close to that mark. In the Pacific, the Trump Administration aggressively pressured Japan and South Korea to foot more of the bill, but as Rapp-Hooper notes, the argument that America spends exorbitantly on the security of other nations conflates the costs of the alliances with the costs of overseas basing. Whether the United States has too many overseas bases or bases in the wrong places is a related but separate issue from weighing the costs and benefits of the alliances themselves.

Another oversight, astutely identified by Rapp-Hooper, is the leverage and control granted by imbalances in security spending. The United States may not be reimbursed for every dollar spent on a security partnership, but we still collect considerable benefits. For example, given its GDP, Japan spends a miniscule amount on defense, but larger Japanese defense expenditures could be destabilizing if interpreted by its neighbors as a provocative act, setting off disputes that the United States would need to manage. Many former rivalries, like those between Japan and South Korea or France and Germany—have been managed through American security assurances. The financial and security costs of otherwise hostile relations are impossible to calculate, but the regional stability afforded by American engagement is an enduring benefit to both American and international security.

Forever Friends?

Shields of the Republic is a traditional defense of alliances in the face of novel challenges. The reforms proposed are also timely but traditional, consisting of a “back to basics” approach that adapts the concepts of forward defense, deterrence, and assurance to today’s challenges of contemporary geopolitical competition.

While Rapp-Hooper clearly sees the fundamental challenges in adapting military arrangements to new non-military threats, her proposed remedies are vague. Even without the Trump administration’s aggressive management style, restructuring alliances for the new era will not be easy. However, this book is more than a policy manual. It is a concise explainer of the driving trends in the past and present of American alliances, and it is vital reading for anyone interested in their future.

Nicholas Romanow is an active-duty Naval Officer stationed in the Washington, D.C., area and a recent graduate of the University of Texas at Austin, where he was also an undergraduate fellow at the Clements Center for National Security. Twitter: @NickRomanow