Halleck began at once to justify the high expectations entertained of him. Order and system followed the erratic administration of his predecessor. Soldiers were subjected to vigorous discipline, but they were given the supplies to which they were entitled, and they were made to feel that they were being employed to some purpose.
The futile and aggravating marches made in pursuit of the elusive guerrillas and bushwhackers, who were never caught, were replaced by well-directed movements striking at the heart of the trouble.
Acting under Gen. Price's orders sometimes, but frequently under their own impulses to commit outrages, inflict blows, and create excitement, a large part of the State was covered by bands of guerrillas who appeared as citizens, were well armed, rode good horses, and were annoyingly successful in sweeping down on the railroad stations, water tanks, bridges, and settlements of Union people, burning, destroying, and creating havoc generally.
Gen. Halleck proclaimed martial law, and issued an order that any man disguised as a peaceful citizen, if caught in the act of burning bridges, etc., should be immediately shot. The troops proceeded to execute this order with good hearts. A large number of the offenders were shot down in the neighborhoods where they had committed their offenses; others were taken before a military commission and condemned to the same fate.
Gens. Pope, Prentiss, Schofield and Henderson were given sufficient forces and ordered to move directly upon the more important bodies of Secessionists who formed a nucleus and support for these depredators. They all did so with good effect.
Gen. Prentiss moved against a force about 3,000 strong operating in Howard, Boone and Calloway Counties, and succeeded in striking them very heavily at Mount Zion Church, where they were dispersed with a loss of 25 killed, 150 wounded, 30 prisoners, 90 horses, and 105 stands of arms.
Gen. Pope operating from Sedalia achieved even better success, capturing Col. Robinson's command of 1,300 men and about 60 officers, 1,000 horses and mules, and 73 wagons loaded with powder, lead and supplies and 1,000 stands of arms.
Gen. Prentiss very effectually cleaned out the State north of the Missouri River, and in conjunction with Gen. Pope's operations south of it, made it so threatening for Gen. Price, who had advanced to the Osage River to support the Secessionists there, that he broke up his camp and rather hurriedly retreated to Springfield.