This book investigates the Mexican War for evidence of modern operational art and answers the question: Does the Mexican War of 1846-1848 hold a unique place in the evolution of modern operational art and, if so, where? The Mexican War represents a distinctly different phase in the evolution of warfare. It was a transitional conflict from the Napoleonic Wars of 1805-1815 to the U.S. Civil War of 1861-1865 and was influenced by the nation's westward expansion and manifest destiny, natural ocean barriers to any serious threat to the nation, and the timing of the Industrial Revolution. The book compares and contrasts those characteristics of modem warfare from the Napoleonic Wars identified in Robert M. Epstein's "Eagles Triumphant: 1809 and the Emergence of Nineteenth-Century Warfare" and the elements of the structure of operational art identified in James J. Schneider's "Vulcan's Anvil: The American Civil War and the Emergence of Operational Art." This process led to the finding that, while operational art in its fullest expression was not practiced during the Mexican War, many of the characteristics from both the Napoleonic War and the Civil War were present.