American Military History, Volume 1 by Richard W. Stewart

With the end of the Civil War, the great volunteer army enlisted for that struggle was quickly demobilized and the U.S. Army became once again a small regular organization. During the ensuing period the Army faced a variety of problems, some old and some new. These included, besides demobilization, occupation duty in the South, a French threat in Mexico, domestic disturbances, Indian troubles, and, within the Army itself, the old awkward relationship between the line and the staff departments. Despite a relative isolation from civilian society during the period 1865–1898, the Army developed professionally, experimented with new equipment of various kinds, and took halting steps toward utilizing the period's new technology in weapons. In a period of professional introspection and physical isolation, the Army still contributed to the nation's civil progress.