J. P. Clark's Preparing for War: The Emergence of the Modern U.S. Army, 1815–1917 fills an important gap in our scholarly understanding of an important institution—the nineteenth-century US Army officer corps. Its wider event horizon due to its uncharacteristically broad chronological range allows for a study of different generations of professional officers that traces how the American army's leadership cadre evolved in relation to developments in both American military history and larger civilian society. Each generation of officers defined, debated, and experienced distinctly [End Page 599] different conceptions of military professionalism. Clark's analytical approach allows his monograph to discern both the American Army's institutional continuities and the significant changes it experienced over the course of the nineteenth century leading up to World War I.
Clark lays out four generations of officers—a foundational generation of veterans of the War of 1812 and antebellum graduates of West Point, a Civil War generation that fought in the nineteenth century's longest conflict, a post−Civil War composite generation of mostly West Point graduates grappling with the earlier conflict's consequences, and a Progressive generation commissioned after 1890 that imported civilian ideas of centralization and bureaucratization into the army. Clark's approach allows him to examine the interaction between predominately military factors (e.g. the size and scale of American wars and the structures of American military institutions) and larger trends in American culture and society. Like many historians, between the analytical poles of continuity and change, Clark gravitates toward the latter—and he also locates the primary causal forces of change in larger American society. As he puts it, "the vertical ties of continuity within the military are less important than the horizontal ties across society. Therefore, each professional generation is more a product of its time than a creation of military institutions" (9).
Clark's approach thus eschews an abstract and social-scientific notion of professionalism, perhaps best embodied in Samuel P. Huntington's The Soldier and the State: The Theory and Politics of Civil-Military Relations (1957). While that work is dated and challenged by most historians, if still cited due to its importance and influence, American military institutions (as Clark himself well knows) remain heavily influenced by conceptions of professionalism that claim to be timeless and enduring. Even the use of history in the American military's educational apparatus tends to gravitate toward the discovery of "lessons learned," which can be applied across wide stretches of time and place. In contrast, perhaps the most trenchant lesson Clark draws from his work for the current American profession of arms is a generational gap in the present US Army between general officers who led troops in Iraq and Afghanistan as senior officers, and junior officers who began their careers in those conflicts at the small unit level. As Clark puts it, "bridging the gaps between these quite different frames of reference is not impossible, but it is unlikely because the bureaucratic artifacts that give an army substance—doctrine, regulations, training plans—rarely [End Page 600] make explicit the assumptions on which they are based. … The most insidious divides are those that go unnoticed" (xi).
Among most professional academic historians, Preparing for War would find ready agreement regarding its argument for the primacy of historical change over political scientists' search for timeless continuities, but where Clark's work makes its biggest contribution is in its longer distinctive chronological spread. William Skelton's An American Profession of Arms: The Army Officer Corps, 1784–1861 (1993) covers the creation of a professional officer corps, but excludes from its coverage the Civil War. It also covers the creation of an American military profession, as opposed to its continuing evolution. Samuel Watson's magisterial two-volume study of the Jacksonian and antebellum US Army, Jackson's Sword: The Army Officer Corps on the American Frontier, 1810–1821 (2012) and Peacekeepers and Conquerors: The Army Officer Corps on the American Frontier, 1821–1846 (2013), covers a narrower period, albeit...