John G. Nicolay, A Short Life of Abraham Lincoln, condensed from Nicolay and Hayes' Abraham Lincoln: A History

[261] the great river itself, and the country lying immediately adjacent to it on either side, became the third principal field of strategy and action, under the necessity of opening and holding it as a great military and commercial highway.

While the intention of the government to open the Mississippi River by a powerful expedition received additional emphasis through Halleck's appointment, that general found no immediate means adequate to the task when he assumed command at St. Louis. Fremont's regime had left the whole department in the most deplorable confusion. Halleck reported that he had no army, but, rather, a military rabble to command, and for some weeks devoted himself with energy and success to bringing order out of the chaos left him by his predecessor. A large element of his difficulty lay in the fact that the population of the whole State was tainted with disloyalty to a degree which rendered Missouri less a factor in the larger questions of general army operations, than from the beginning to the end of the war a local district of bitter and relentless factional hatred and guerrilla or, as the term was constantly employed, “bushwhacking” warfare, intensified and kept alive by annual roving Confederate incursions from Arkansas and the Indian Territory in desultory summer campaigns.