Explanation: At the start of the war, General-in-Chief Winfield Scott developed a plan that would use a Union naval blockade of the Confederate coastline to stop any military and commercial shipments that would aid the Confederate cause.
The first military strategy offered to Pres. Abraham Lincoln for crushing the rebellion of Southern states was devised by Union General-in-Chief Winfield Scott. From April 1 through early May 1861 Scott briefed the president daily, often in person, on the national military situation; the results of these briefings were used by Scott to work out Union military aims.
About May 3rd, Scott told his protégé, Maj. Gen. George B. McClellan, that he believed an effective "Blockade" of Southern ports, a strong thrust down the Mississippi Valley with a large force, and the establishment of a line of strong Federal positions there would isolate the disorganized Confederate nation "and bring it to terms."
Contemporary sources said McClellan called it Scott's "boa-constrictor" plan. Scott then presented it to the president, in greater detail, proposing that 60,000 troops move down the Mississippi with gunboats until they had secured the river from Cairo, Ill., to the Gulf, which, in concert with an effective blockade, would seal off the South. Then, he believed, Union troops should stop, waiting for Southern Union sympathizers to turn on their Confederate governors and compel them to surrender. It was his belief that sympathy for secession was not as strong as it appeared and that isolation and pressure would make the "fire-eaters" back down and allow calmer heads to take control.
But the war-fevered nation wanted combat, not armed diplomacy, and the passive features of Scott's plan were ridiculed as a proposal "to squeeze the South to military death." The press, recalling McClellan's alleged "boa-constrictor" remark, named the plan after a different constricting snake, the anaconda.
The Anaconda Plan was drawn up to end the Civil War in favor of the Union. The plan was adopted in 1862, involving 4 main parts:
Blockade the coast of the South to prevent the export of cotton, tobacco, and other cash crops from the South and to keep them from importing much needed war supplies.
Divide the South by controlling the Mississippi River to cut the South off from the west.
Divide the South by capturing the Tennessee River Valley and marching through Georgia to the coast.
Capture Richmond, Virginia, the capital of the Confederate States of America.
Although the plan was devised early in the war, it was derided by several newspapers and was reluctantly adopted by the Union's leaders. The plan as originally conceived by Scott also advised passivity, in that it suggested that once the Southern states were effectively cut off from their resources, the Union should wait for capitulation. Nonetheless, the particulars of the Plan were all carried through, the first 3 proving indeed to be the most decisive factors of the war:
Pres. Lincoln called for a blockade of the South on April 19th, 1861, 6 days after the fall of Fort Sumter. The blockade itself, thought to be an impossible task against 3000 miles of highly irregular coastline, was an unparalleled success within the first 6 months, and nearly impregnable within the first 2 years. The blockade accounted for the vast increase in the price of cotton abroad and the extreme scarcity of manufactured goods in the South by the end of the war, contributing to the Confederacy's defeat. It was the most successful naval blockade to date, and the first one carried out exclusively by the use of a national navy, without employing privateers.
Control of the Mississippi River would prove decisive in the Civil War as well; Pres. Jefferson Davis called Vicksburg the "vital point" of the Confederacy. Although the Eastern Theater was closer to the major centers of population and therefore often drew more attention, the Mississippi River represented a major strategic resource that would, if captured by the North, allow for the movement of men and material into the very heart of the South. Maj. Gen. Ulysses S. Grant's successful Vicksburg campaign effectively cemented Union control of the Mississippi River, and began the slow death knell for the Confederacy.
The Tennessee River Valley was also very important to the South. Nashville, Tennessee was served by 5 railroads during the war, and the state of Tennessee was home to the Cumberland and Tennessee Rivers, making it an ideal point for marshalling and distributing resources. Indeed, the South's second largest ironworks was in Clarksville, Tennessee, on the Kentucky border, near a bend in the Cumberland River. As soon as Tennessee voted for secession, the Confederacy began to stockpile weapons and supplies at Nashville, making it the center of distribution and manufacture for Southern war goods of all kinds. They built Fort Henry and Fort Donelson on the Tennessee and Cumberland rivers, respectively, to protect this important region. However, their defenses did not hold, and after Grant's taking of the garrison at Fort Donelson on February 16, 1862, commander Gen. Albert Sidney Johnston knew he could no longer hold Nashville and withdrew. The supply depot would remain in Union hands until the end of the war. The loss of Tennessee in general and Nashville in particular dealt a crippling blow to the Confederate cause.
Grant occupied Richmond, Virginia in April of 1865, shortly before the surrender of Gen. Robert E. Lee's Army, but the city had no particular strategic value, serving only as a blow to Confederate morale.
The Western Theater that figured most prominently in the Anaconda Plan and in the actual defeat of the Confederacy. Without the loss of the Mississippi River and the Tennessee Valley, the supposed vast differences in resources between the Union and the Confederate Armies would have been greatly lessened. It was Grant's successes in the West that brought him to the attention of the Lincoln and paved his way for command of the Union forces. Indeed, once the West was lost, Lee's defeat became a mere question of time. Had Lee not been blockaded, or at least still held the Tennessee Valley, he would have had resources enough to drag the war on interminably; quite possibly long enough to force a settlement with the Union.