Reviewed by: Illusions of Empire: The Civil War and Reconstruction in the U.S.-Mexico Borderlands by William S. Kiser Patrick T. Troester Illusions of Empire: The Civil War and Reconstruction in the U.S.-Mexico Borderlands. By William S. Kiser. America in the Nineteenth Century. (Philadelphia: University of Pennsylvania Press, 2022. Pp. viii, 262. $55.00, ISBN 978-0-8122-5351-1.) William S. Kiser’s Illusions of Empire: The Civil War and Reconstruction in the U.S.-Mexico Borderlands explores the chaotic history of international relations during the American Civil War and the French Intervention in Mexico (1861–1867). In this vast region beyond the control of any single state or faction, the two overlapping wars joined with long-standing local factors—especially geographic isolation, northern Mexican regionalism, Anglo-American territorial ambitions, Native power, and a porous international boundary—to favor what Kiser calls “irregular diplomacy” (p. 7). As conventional diplomatic channels failed, actors on all sides employed “a kaleidoscopic array of personal scheming,” which involved not only official diplomatic agents but also military commanders, state governors, and local elites, as well as independent Native peoples and stateless groups of filibusters, bandits, and revolutionaries (p. 3). Driven by competing but interconnected “illusions of empire,” this motley cast forged a shifting set of informal local agreements to advance vital strategic goals reaching far beyond the border region. Confederates courted individual Mexican governors, the Benito Juárez administration, and Franco-Mexican imperialists to circumvent the Union blockade and pursue a slaveholding empire in Latin America and the Pacific. U.S. officials used irregular diplomacy to protect and grow their own transcontinental empire, hoping to [End Page 157] leverage Mexican support against Confederate rebels, Native peoples, and the creation of a European-backed monarchy on their southern border. Meanwhile, Mexican leaders at the regional and national levels bent all these efforts to their own ends, aiming to preserve national independence, protect local power, or enrich themselves. After Appomattox, U.S. leaders turned irregular diplomacy toward the goals of Greater Reconstruction, using these methods to consolidate national sovereignty north of the border and to promote Mexican leaders favorable to the expanding interests of American capitalism. To reconstruct this tangled web of diplomacy, commerce, and violence, Kiser draws on the diplomatic and military records of the U.S. and Confederate governments alongside a broad array of secondary literature and published primary sources in English and Spanish. After tracing irregular diplomacy’s antebellum roots, Illusions of Empire follows a loose chronological arc through the 1860s, with chapters alternating between the eastern and western halves of the border region. Given this multinational focus, the main shortcoming of this book is a lack of Mexican archival research. Although Kiser’s attention south of the modern border far exceeds that of most previous works, the voices of northern Mexican leaders appear almost entirely through their politically fraught communications with outsiders—those pursuing illusions of empire with ambivalence toward the local people and resources they sought to manipulate. As a result, the internal complexities of regional politics across northern Mexico often remain underexplored, and readers gain little direct sense of the imperial and national visions guiding borderlands power brokers themselves, even as Kiser convincingly shows their far-reaching influence. The book also misses the opportunity to engage with recent scholarship on mid-nineteenth-century Mexico by Erika Pani, Luis Medina Peña, Pablo Mijangos y González, and others, which has greatly enhanced our understandings of this chaotic period, often with illuminating transnational and comparative analysis. Despite these limitations, however, Kiser’s expansive history of borderlands diplomacy and intrigue fills important gaps in the historiographies of the Civil War era, U.S. foreign relations, North American imperialism, and the U.S.-Mexico borderlands. It will be a valuable read for scholars in all these fields, particularly those with transnational and continental interests. Perhaps most important, Kiser goes beyond simply linking or comparing events in the United States and Mexico to recover the deep entanglement of the Civil War and the French Intervention, while also showing the critical importance of events in the border region to both conflicts and to the broader geopolitical history of North America. Patrick T...