l war against the South.
             While Lincoln mobilized forces, he moved aggressively to keep Maryland, Delaware, and western Virginia in the Union, and cautiously worked to do the same in Kentucky and Missouri. Meanwhile, the decision by Virginia, North Carolina, Tennessee, and Arkansas to join the Confederacy made it clear that the Confederacy was now a formidable opponent.
             Setting War Aims and Devising Military Strategies
             Initial encounters convinced both sides that a sustained military effort would be required to achieve their respective goals. Southerners were aware that all they needed to do was fight a defensive war, while Lincoln concluded that the North needed a decisive military victory to crush the rebellion. As Union forces pursued a campaign to take Richmond in 1861, which soon became bogged down, Confederate forces moved north through Virginia to invade Maryland in 1862. In the West, Union forces invaded Kentucky and Tennessee, where they faced less resistance. In each campaign, the fighting escalated into ever larger battles with higher casualties. While the North had put the Confederacy on the defensive in the West by the spring of 1863, both sides were locked in a stale
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