Stephen A. Townsend's The Yankee Invasion of Texas (Texas A&M University Press, 2006) is a concise history of the Union's Rio Grande Expedition, and a great companion piece to related works, such as David C. Edmonds' Yankee Autumn in Acadiana and Richard Lowe's The Texas Overland Expedition of 1863. These books recount the land thrust into NE Texas via Louisiana, diverting Confederate men, attention, and resources from the Union naval expedition to the mouth of the Rio Grande. Ed Cotham's Sabine Pass also should be read by those interested in learning about 1863 seaborne operations off the Texas coast.
The bulk of The Yankee Invasion of Texas covers the period from October 1863 until the Spring of 1864, when most of the Federal troops were withdrawn. The expedition was highly successful in seizing the mouth of the Rio Grande and hindering the cross-border cotton trade with Mexico. Troops then were sent up the coast, defeating Confederate garrisons, occupying the barrier islands, and closing down ports up to the Matagorda peninsula. There the offensive fizzled out.
The book illustrates the typical pattern of early success of Union coastal operations against unprepared Confederate positions with weak garrisons followed by consolidation and general inaction. The commanders on the ground and the higher military and political leadership cannot agree on the next step in planning and impressive gains go unexploited. Success is not reinforced. Soon the cries for concentration at "more active fronts" lead to demands for the withdrawal of troops from the coast. Inland advances by disposable forces are either defeated or are too small to perform useful tasks, only reinforcing the higher command's view of the situation and desire for withdrawal and troop concentration elsewhere. Failure becomes self-fulfilling.
Yankee Invasion is a thin volume that yields more than enough depth of information inside to satisfy a wide range of reader interests. The military aspects of the invasion are detailed enough to please demanding students and the author additionally provides useful summarizations of the invasion's political and economic contexts. Townsend enlightens readers with his discussion of Texas unionism. He also points out the critical importance of the border trade and the complex motivations of the Hispanic population on both sides of the border (with French and Mexican pro-Imperialist concerns thrown in). It really is a great read, combining a high degree of scholarship with engaging prose. Highly recommended.