American Civil War: Joseph E. Johnston replaces Braxton Bragg as commander of the Confederate Army of Tennessee.

Joseph Eggleston Johnston (February 3, 1807 March 21, 1891) was an American career army officer, serving with distinction in the United States Army during the MexicanAmerican War (18461848) and the Seminole Wars. After Virginia seceded from the Union, he entered the Confederate States Army as one of its most senior general officers.

Johnston was trained as a civil engineer at the United States Military Academy at West Point, New York, graduating in the same class as Robert E. Lee. He served in Florida, Texas, and Kansas. By 1860 he achieved the rank of brigadier general as Quartermaster General of the U.S. Army.

Johnston's effectiveness in the American Civil War was undercut by tensions with Confederate president Jefferson Davis. Victory eluded him in most campaigns he personally commanded. He was the senior Confederate commander at the First Battle of Bull Run in July 1861, but the victory is usually credited to his subordinate, P.G.T. Beauregard. Johnston defended the Confederate capital of Richmond, Virginia, during the 1862 Peninsula Campaign, withdrawing under the pressure of Union Maj. Gen. George B. McClellan's superior force. He suffered a severe wound at the Battle of Seven Pines, and was replaced by Robert E. Lee.

In 1863, Johnston was placed in command of the Department of the West. In 1864, he commanded the Army of Tennessee against Union Maj. Gen. William Tecumseh Sherman in the Atlanta Campaign. In the final days of the war, Johnston was returned to command of the few remaining forces in the Carolinas Campaign. Union generals Ulysses S. Grant and Sherman both praised his actions in the war, and became friends with Johnston afterward.

After the war, Johnston served as an executive in the railroad and insurance businesses. He was elected as a Democrat in the United States House of Representatives, serving a single term. He was appointed as commissioner of railroads under Grover Cleveland. Johnston died of pneumonia 10 days after attending Sherman's funeral in the pouring rain.

The American Civil War (April 12, 1861 – May 9, 1865; also known by other names) was a civil war in the United States between the Union (states that remained loyal to the federal union, or "the North") and the Confederacy (states that voted to secede, or "the South"). The central cause of the war was the status of slavery, especially the expansion of slavery into territories acquired as a result of the Louisiana Purchase and the Mexican–American War. On the eve of the Civil War in 1860, four million of the 32 million Americans (~13%) were enslaved black people, almost all in the South.The practice of slavery in the United States was one of the key political issues of the 19th century. Decades of political unrest over slavery led up to the Civil War. Disunion came after Abraham Lincoln won the 1860 United States presidential election on an anti-slavery expansion platform. An initial seven southern slave states declared their secession from the country to form the Confederacy. Confederate forces seized federal forts within territory they claimed. The last-minute Crittenden Compromise tried to avert conflict but failed; both sides prepared for war. Fighting broke out in April 1861 when the Confederate army began the Battle of Fort Sumter in South Carolina, just over a month after the first inauguration of Abraham Lincoln. The Confederacy grew to control at least a majority of territory in eleven states (out of the 34 U.S. states in February 1861), and asserted claims to two more. Both sides raised large volunteer and conscription armies. Four years of intense combat, mostly in the South, ensued.

During 1861–1862 in the war's Western Theater, the Union made significant permanent gains—though in the war's Eastern Theater the conflict was inconclusive. On January 1, 1863, Lincoln issued the Emancipation Proclamation, which made ending slavery a war goal, declaring all persons held as slaves in states in rebellion "forever free." To the west, the Union destroyed the Confederate river navy by the summer of 1862, then much of its western armies, and seized New Orleans. The successful 1863 Union siege of Vicksburg split the Confederacy in two at the Mississippi River. In 1863, Confederate General Robert E. Lee's incursion north ended at the Battle of Gettysburg. Western successes led to General Ulysses S. Grant's command of all Union armies in 1864. Inflicting an ever-tightening naval blockade of Confederate ports, the Union marshaled resources and manpower to attack the Confederacy from all directions. This led to the fall of Atlanta in 1864 to Union General William Tecumseh Sherman and his march to the sea. The last significant battles raged around the ten-month Siege of Petersburg, gateway to the Confederate capital of Richmond.

The Civil War effectively ended on April 9, 1865, when Confederate General Lee surrendered to Union General Grant at the Battle of Appomattox Court House, after Lee had abandoned Petersburg and Richmond. Confederate generals throughout the Confederate army followed suit. The conclusion of the American Civil War lacks a clean end date: land forces continued surrendering until June 23. By the end of the war, much of the South's infrastructure was destroyed, especially its railroads. The Confederacy collapsed, slavery was abolished, and four million enslaved black people were freed. The war-torn nation then entered the Reconstruction era in a partially successful attempt to rebuild the country and grant civil rights to freed slaves.

The Civil War is one of the most studied and written about episodes in the history of the United States. It remains the subject of cultural and historiographical debate. Of particular interest is the persisting myth of the Lost Cause of the Confederacy. The American Civil War was among the earliest to use industrial warfare. Railroads, the telegraph, steamships, the ironclad warship, and mass-produced weapons saw wide use. In total the war left between 620,000 and 750,000 soldiers dead, along with an undetermined number of civilian casualties. President Lincoln was assassinated just five days after Lee's surrender. The Civil War remains the deadliest military conflict in American history. The technology and brutality of the Civil War foreshadowed the coming World Wars.