<P> The Civil War began on April 12, 1861, when elements of 100,000 Confederate forces attacked a U.S. military installation at Fort Sumter in South Carolina . In response to the attack, on April 15, Lincoln called on the states to send detachments totaling 75,000 troops to recapture forts, protect the capital, and "preserve the Union", which in his view still existed intact despite the actions of the seceding states . The two armies had their first major clash at the First Battle of Bull Run (Battle of Manassas), ending in a Union defeat, but, more importantly, proved to both the Union and Confederacy that the war would be much longer and bloodier than originally anticipated . </P> <P> The war soon divided into two theaters: Eastern and Western . In the western theater, the Union was relatively successful, with major battles, such as Perryville and Shiloh along with Union gunboat dominance of navigable rivers producing strategic Union victories and destroying major Confederate operations . </P> <P> Warfare in the Eastern theater began poorly for the Union as the Confederates won at Manassas Junction (Bull Run), just outside Washington . Major General George B. McClellan was put in charge of the Union armies . After reorganizing the new Army of the Potomac, McClellan failed to capture the Confederate capital of Richmond, Virginia in his Peninsula Campaign and retreated after attacks from newly appointed Confederate General Robert E. Lee . Meanwhile, both sides concentrated in 1861--62 on raising and training new armies . The main action was Union success in controlling the border states, with Confederates largely driven out of Maryland, West Virginia (a new state), Kentucky and Missouri . The autumn 1862 Confederate campaign into Maryland was designed to hurt Union morale and win European support . It ended with Confederate retreat at the Battle of Antietam, and Lincoln's warning he would issue an Emancipation Proclamation in January 1863 if the states did not return . Making slavery a central war goal Energized Republicans in the North, as well as their enemies, the anti-war Copperhead Democrats . It ended the risk of British and French intervention . </P> <P> Lee's smaller army won at the Battle of Fredericksburg late in 1862, causing yet another change in commanders . Lee won again at the Battle of Chancellorsville in May 1863, while losing his top aide, Stonewall Jackson . But Lee pushed too hard and ignored the Union threat in the west . Lee invaded Pennsylvania in search of supplies and to cause war - weariness in the North . In perhaps the turning point of the war, Lee's army was badly beaten at the Battle of Gettysburg, July 1--3, 1863, and barely made it back to Virginia . On the homefront, industrial expansion in the North expanded dramatically, using its extensive railroad service, and moving industrial workers into munitions factories . Foreign trade increased, with the United States providing both food and cotton to Britain, And Britain sending in manufactured products and thousands of volunteers for the Union Army (plus a few to the Confederates). The British operated blockade runners bringing in food, luxury items and munitions to the Confederacy, bringing out tobacco and cotton . The Union blockade increasingly shut down Confederate ports, and by late 1864 the blockade runners Were usually captured before they could make more than handful of runs . </P>

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