Peninsula campaign

The Peninsula campaign (also known as the Peninsular campaign) of the American Civil War was a major Union operation launched in southeastern Virginia from March to July 1862, the first large-scale offensive in the Eastern Theater. The operation, commanded by Major General George B. McClellan, was an amphibious turning movement against the Confederate States Army in Northern Virginia, intended to capture the Confederate capital of Richmond. Despite the fact that Confederate spy Thomas Nelson Conrad had obtained documents describing McClellan's battle plans from a double agent in the War Department, McClellan was initially successful against the equally cautious General Joseph E. Johnston, but the emergence of the more aggressive General Robert E. Lee turned the subsequent Seven Days Battles into a humiliating Union defeat.

McClellan landed his army at Fort Monroe and moved northwest, up the Virginia Peninsula. Confederate Brigadier General John B. Magruder's defensive position on the Warwick Line caught McClellan by surprise. His hopes for a quick advance foiled, McClellan ordered his army to prepare for a siege of Yorktown. Just before the siege preparations had been completed, the Confederates, now under the direct command of Johnston, began a withdrawal toward Richmond. The first heavy fighting of the campaign occurred during the Battle of Williamsburg in which the Union troops managed some tactical victories, but the Confederates continued their withdrawal. An amphibious flanking movement to Eltham's Landing was ineffective in cutting off the Confederate retreat. During the Battle of Drewry's Bluff, an attempt by the US Navy to reach Richmond by way of the James River was repulsed.

As McClellan's army reached the outskirts of Richmond, a minor battle occurred at Hanover Court House, but it was followed by a surprise attack by Johnston at the Battle of Seven Pines or Fair Oaks. The battle was inconclusive, with heavy casualties, but it had lasting effects on the campaign. Johnston was wounded by a Union artillery shell fragment on May 31 and replaced the next day by the more aggressive Robert E. Lee, who reorganized his army and prepared for offensive action in the final battles of June 25 to July 1, which are popularly known as the Seven Days Battles. The result was that the Union army was unable to enter Richmond, and both armies remained intact.

On August 20, 1861, Maj. Gen. George B. McClellan formed the Army of the Potomac, with himself as its first commander. During the summer and fall, McClellan brought a high degree of organization to his new army, and greatly improved its morale by his frequent trips to review and encourage his units. It was a remarkable achievement, in which he came to personify the Army of the Potomac and reaped the adulation of his men. He created defenses for Washington that were almost impregnable, consisting of 48 forts and strong points, with 480 guns manned by 7,200 artillerists.

On November 1, 1861, Gen. Winfield Scott retired and McClellan became general in chief of all the Union armies. The president expressed his concern about the "vast labor" involved in the dual role of army commander and general in chief, but McClellan responded, "I can do it all."

On January 12, 1862, McClellan revealed his intentions to transport the Army of the Potomac by ship to Urbanna, Virginia, on the Rappahannock River, outflanking the Confederate forces near Washington, and proceeding 50 miles (80 km) overland to capture Richmond. On January 27, Lincoln issued an order that required all of his armies to begin offensive operations by February 22, Washington's birthday. On January 31, he issued a supplementary order for the Army of the Potomac to move overland to attack the Confederates at Manassas Junction and Centreville. McClellan immediately replied with a 22-page letter objecting in detail to the president's plan and advocating instead his Urbanna plan, which was the first written instance of the plan's details being presented to the president. Although Lincoln believed his plan was superior, he was relieved that McClellan finally agreed to begin moving, and reluctantly approved. On March 8, doubting McClellan's resolve, Lincoln called a council of war at the White House in which McClellan's subordinates were asked about their confidence in the Urbanna plan. They expressed their confidence to varying degrees. After the meeting, Lincoln issued another order, naming specific officers as corps commanders to report to McClellan (who had been reluctant to do so prior to assessing his division commanders' effectiveness in combat, even though this would have meant his direct supervision of twelve divisions in the field).

Before McClellan could implement his plans, the Confederate forces under General Joseph E. Johnston withdrew from their positions before Washington on March 9, assuming new positions south of the Rappahannock, which completely nullified the Urbanna strategy. McClellan retooled his plan so that his troops would disembark at Fort Monroe, Virginia, and advance up the Virginia Peninsula to Richmond. However, McClellan came under extreme criticism from the press and the Congress when it was found that Johnston's forces had not only slipped away unnoticed, but had for months fooled the Union Army through the use of Quaker Guns.

A further complication for the campaign planning was the emergence of the first Confederate ironclad warship, CSS Virginia, which threw Washington into a panic and made naval support operations on the James River seem problematic. In the Battle of Hampton Roads (March 8–9, 1862), Virginia defeated wooden U.S. Navy ships blockading the harbor of Hampton Roads, Virginia, including the frigates USS Cumberland and USS Congress on March 8, calling into question the viability of any of the wooden ships in the world. The following day, the USS Monitor ironclad arrived at the scene and engaged with the Virginia, the famous first duel of the ironclads. The battle, although inconclusive, received worldwide publicity. After the battle, it was clear that ironclad ships were the future of naval warfare. Neither ship severely damaged the other; the only net result was keeping Virginia from attacking any more wooden ships.