The initial Union strategy involved blockading Confederate ports to cut off cotton exports and prevent the import of manufactured goods; and using ground and naval forces to divide the Confederacy into three distinct theaters. These were the far western theater, west of the Mississippi River; the western theater, between the Mississippi and the Appalachians; and the eastern theater, in Virginia. Ridiculed in the press as the "Anaconda Plan," after the South American snake that crushes its prey to death, this strategy ultimately proved successful. Although about 90 percent of Confederate ships were able to break through the blockade in 1861, this figure was cut to less than 15 percent a year later. Although the Union army suffered repeated defeats and stalemates in the East, victories in the western theater undermined the hopes for Confederate independence.
The following letter suggests how active a role President Lincoln played in the formulation of military strategy.
The command of the Department of the West having devolved upon you, I propose to offer you a few suggestions. Knowing how hazardous it is to bind down a distant commander in the field to specific lines and operations, as so much always depends upon a knowledge of localities and passing events. It is intended therefore to leave a considerable margin for the exercise of your judgement and discretion.
The main rebel army (Price's) west of the Mississippi is believed to have passed Dade County in full retreat upon North Western Arkansas, leaving Missouri almost freed from the enemy, excepting in the South East of the State. Assuming this basis of fact, it seems desirable as you are not likely to overtake Price, and are in danger of making too long a line from your own base of supplies and reinforcements, that you should give up the pursuit, halt your main army, divide it into two corps of observation, one occupying Sedalia and the other Rolla, the present termini of Railroads, then recruit the condition of both corps by re establishing and improving their discipline and instruction, perfecting their clothing and equipments and providing less uncomfortable quarters. Of course, both Railroads must be guarded and kept open, judiciously employing just so much force as is necessary for this. From these two points Sedalia and Rolla, and especially in judicious cooperation with Lane on the Kansas border, it would be so easy to concentrate and repel any army of the enemy returning on Missouri from the South West, that it is not probable any such attempt to return will be made by the enemy before or during the approaching cold weather. Before Spring the people of Missouri will probably be in no favorable mood to renew for next year the troubles which have so much afflicted and impoverished them during this.
If you adopt this line of policy, and if, as I anticipate, you will see no enemy in great force approaching, you will have a surplus of force, which you can withdraw form these points, and direct to others as may be needed; the Railroads furnishing ready means of reinforcing the main points, if occasion requires. Doubtless local uprising will, for a time, continue to occur: but these can be met by detachments, and local forces of our own, and will, ere long, tire out of themselves.
While, as stated in the beginning of this letter a large discretion must be, and is left with yourself, I feel sure that an indefinite pursuit of Price, or an attempt, by this long and circuitous route, to reach Memphis, will be exhaustive beyond endurance, and will end in the loss of the whole of the force engaged in the attempt.