Paul J. Heer's Mr. X and the Pacific charts the career of one of America's most famous diplomats, George F. Kennan, in relation to his influence on US Cold War policymaking in East Asia. Overwhelmingly associated with his expertise on the Soviet Union, Kennan is best remembered for articulating the strategic concept of containment: a policy to curtail Soviet expansionism that underpinned US Cold War policy under the Truman Doctrine. In this thought-provoking book, Heer convincingly demonstrates how Kennan's strategy of containment related to American policymaking in the Pacific, analysing the competing and contradictory ways Kennan sought to apply this strategic concept to East Asia.

Utilizing US archival material, as well as personal correspondence and interviews, Heer addresses American attempts to conduct the Cold War in the Pacific through the lens of Kennan's time as director of the State Department's Policy Planning Staff between 1947 and 1950. Combining a chronological and a country-by-country structure, Heer examines how Kennan's interpretation of a “defensive perimeter concept” (91–92) for East Asia sought to limit US commitments on the Asian mainland whilst creating a “demilitarized but neutral” (2) Japan as a focal point for US engagement. Heer traces the rise and fall of this strategic concept through case studies of US policy towards China, Japan, and Korea, before moving on to Kennan's life post-policymaking and his increased frustration over interpretations of his policy in Vietnam. Each case study is aptly interrogated, all whilst negotiating the intricate set of personal and professional relationships that helped and hindered Kennan's policymaking.

Heer's argument – that Kennan's influence on US policymaking in East Asia was “profound” if “ephemeral” (2) – is a compelling one. Heer observes that Kennan's preoccupation was always the Soviet Union, and inevitably viewed developments in Asia through a Soviet lens. Yet Heer also notes how Kennan's vision of a defensive-perimeter concept did eventually gain traction in the upper echelons of government, particularly in relation to American policy towards minimal aid to Nationalist China and demilitarizing Japan. Ultimately, however, Heer claims Kennan's strategic framework was made redundant by the onset of the Korean War, where Kennan's narrow strategic focus and inability to reconcile American intervention with a concern for maintaining US prestige left little room for his framework against an acute sense of advancing communist threat on the continent.

Firmly rooted in the new foreign-relations biography, Heer's text is a welcome addition to the growing literature looking to rebuke the maxim of biography as an intellectual backwater for academic enquiry. Reflective of the cultural turn in diplomatic history, Heer's text openly embraces cultural considerations around race, as well as issues of emotion and personal politics, to better illuminate Kennan's intellectual and policymaking parameters. Heer considers how relationships with superiors like George C. Marshall and Dean Acheson both actively aided and inhibited his attempts to influence policy, as the latter's tenure as Secretary of State saw Kennan's influence within the department diminish and his alienation from government increase. Although discussed in scholarship elsewhere, his attention to Kennan's intellectual assumptions around Asian peoples – described as “dismissive” (124) and “condescending” (125) – paints a picture of Kennan as a Eurocentric and orientalist thinker whose presumptions about Asian peoples’ inability for self-government often clouded his judgement.

In this sense, Heer's text moves away from episodical accounts of the life and times of a historical subject, opting to treat Kennan's career as part of a wider understanding of the expansion of the Cold War into East Asia. Heer intelligently integrates Kennan's experience into broader American foreign-policy considerations like the Chinese Civil War, the conflict in Korea, and American entry into Vietnam, depicting a policymaker who was ironically hamstrung by the ambiguity of his own thinking on East Asia.

Unfortunately, this approach also points out some of the flaws in foreign-relations biography. In its focus on elite American diplomacy, Heer's analysis inevitably negates the agency of Asian states and actors in order to focus on the development of Kennan's ideas. This is more a criticism of foreign-relations biography as methodology, as any structure built around an individual actor naturally means downplaying the significance of wider, systemic historical forces. Yet the text makes little attempt to position Kennan's policies against the varying political contexts of East Asia during the expansion of the Cold War, focussing instead on his manoeuvres within the administration to garner support. This is most evident in the treatment of the defensive-perimeter concept in Southeast Asia, where Heer's analysis often sidesteps the complicated, local contexts that faced Southeast Asian nations like the Philippines. In Manila, for example, any consideration of American strategic interests and a US military presence provoked complicated reactions from local actors, who were acutely aware of the American imperial legacy in the islands. Navigating a complex terrain of heightened nationalist sentiment against American imperialism and encroaching Cold War conflict, Filipino elites consistently faced challenges in integrating a US military presence on the archipelago which moved far beyond the strategic considerations discussed in Washington. Here, a fuller consideration of how Kennan's strategic vision for East Asia interacted with the localities they were addressing would help flesh out the promises and pitfalls of Kennan's defensive-perimeter concept.

Ultimately, however, Heer's text deals in both depth and brevity with one of America's most influential Cold Warriors in relation to his underexplored legacy in Asian policymaking. His research on Kennan points to an enduring tension in American relations with East Asia between engagement and isolation, and addresses contemporary debates about the limitations of US power in a dynamic, diverse, and rapidly changing region. For this reason, Heer's text is an important read for historians of the Cold War and practitioners of US–Asian relations alike.