After the seizure of Fort Sumter in April 1861, both the North and the South prepared for war. The North had a distinct economic advantage because almost all of the nation’s factories were been located in the Northeast and Mid-Atlantic states. The Union also had nearly twice the South’s population and thus a larger pool of young men to serve in the army.
However, the North’s new recruits were largely untrained, and most of the best military commanders had been from the South. Abraham Lincoln offered command of the main Union army to Robert E. Lee, but Lee, though he disapproved of secession, felt compelled to fight for his home state of Virginia.
Lincoln therefore ended up putting General George McClellan in command of the Army of the Potomac. “Little Mac,” as he was called, though still only in his thirties, was probably the most popular man in the army in his day. Despite McClellan’s popularity with the troops, however, he was poorly regarded among civilian leaders in Washington and had a reputation for having a rather large ego. Throughout the war, McClellan proved timid, and he always made some excuse to avoid engaging Lee’s Army of Northern Virginia.
War preparations took some time, so it was not until three months after Fort Sumter that Union and Confederate troops met again at the First Battle of Bull Run in Virginia, between Washington, D.C., and Richmond. Still believing that the war was a trifling matter that would be over quickly, a number of government officials and spectators from both sides came to “observe” the battle, some even packing picnic lunches. By the end of the day, Union forces had lost and were forced to retreat. The loss shocked Northerners out of their complacency and prompted them to prepare more seriously for the struggle ahead. Meanwhile, many Southerners interpreted the victory as an indicator of an early end to the war and as decisive proof that most Northerners didn’t have the will to fight.
Just as Northerners were shocked into reality by the First Battle of Bull Run, so too were Southerners by the Battle of Shiloh. In April 1862, Union General Ulysses S. Grant engaged Confederate forces at Shiloh, Tennessee, in an incredibly bloody battle. Tens of thousands of men died. By the end of the bloodbath, Grant had won and demonstrated to the Confederates that Lincoln was serious about maintaining the Union. Southerners got the message and dug in for a longer war.
Rather than wait around for the enemy to attack him, Lee made an aggressive push into the border states to try to defeat the Union on its own turf. He also hoped that a Confederate victory in Maryland would convince the state legislature to secede. In September 1862, Lee’s army met General George McClellan’s troops at the Battle of Antietam, which resulted in more than 23,000 casualties—the bloodiest single day of battle of the entire war. Lee was forced to retreat back to Confederate territory.