Explanation: On all fronts, superior Union resources in manpower and material, and the strangling Union naval blockade, were beginning to overwhelm the South.
Gen. Robert E. Lee argued for a second invasion of the north. Lee stated that such an offensive would relieve Richmond, allow Confederates to gather supplies from the Pennsylvania countryside, encourage Northern peace movement, re-open the possibility of European recognition, and perhaps result in the capture of the Union capitol and other Northern cities. His plan was approved.
The spectacular Confederate victory at Chancellorsville during the 1st week of May did not relieve the enormous problems confronting the Confederacy. On all fronts, superior Northern resources in manpower and material were beginning to overwhelm the South. With the Confederacy strangled by the Union naval blockade, wracked by worsening inflation, and outnumbered from Virginia to Mississippi, authorities wrestled with the strategic options.
Pres. Jefferson Davis, cabinent members, and generals conferred during May. Gen. Robert E. Lee, commander of the Army of Northern Virginia, opposed plans to send detachments from his army to relieve Tennessee and a beseiged Vicksburg, arguing for a 2nd invasion of the North. Such an offensive, Lee stated, would relieve Richmond, allow the Confederates to garner supplies from the lush Pennsylvania countryside, encourage the Northern peace movement, reopen the possibility of European recognition, and perhaps result in the capture of Washington, D.C. and other Northern cities. The civilian authorities approved Lee's plan.
On June 3rd, the advance elements of the reorganized Confederate army abandoned their lines at Fredericksburg, with only Lt. Gen. Ambrose P. Hill's III Corps remaining to deceive the Union Maj. Gen. Joseph Hooker. By the 8th, Lee jad concentrated 2 infantry corps and his cavalry at Culpeper, east of the Blue Ridge Mountains. Confronted with rumors of a Confederate offensive, Hooker ordered cavalry reconnaissances that resulted in battles at Franklin's Crossing on the 5th and Brandy Station on the 9th.
Lee's march accelerated on the 10th when Lt. Gen. Richard S. Ewell's II Corps, Lt. gen. Thomas J. "Stonewall" Jackson's former command, moved toward the Shenandoah Valley. Marching swiftly, on the 13th, ewell's foot cavalry reached Winchester, where Maj. Gen. Robert H. Nilroy's Union force was stationed. Ewell attacked the next day, and on the 15th, virtually destroying the Union command. With the lower valley cleared of Union troops, Lee's army drove across the Potomac River into maryland. By the 25th, the III Corps of Confederate infantry had entered Northern territory.
Hooker, meanwhile, reacted swiftly to the invasion. Marching northward, his army remained between the Confederates and Washington, D.C. However, he complained about superior Confederate numbers and the lack of support from the Lincoln administration. When he quarreled with Maj. Gen. Henry W. Halleck, Union gen.-in-chief, over the garrison at Harpers Ferry, the army commander submitted his resignation. Lincoln accepted it, appointing Maj. Gen. George G. Meade to command on the 28th.
On the day Meade replaced hooker, lee learned through a spy that the entire Union army lay north of the Potomac. The Confederate army had been stumbling blindly into Pennsylvania since the 24th, when Maj. Gen. J.E.B. Stuart abandoned Lee's flank for a raid around the Union army. Censured for his near-defeat at Brandy Station, Stuart, using Lee's discretionary orders, had cantered off in another dramatic ride. His absence crippled the Confederate invasion, denying Lee vital intelligence.
When Lee learned of Meade's position, he rapidly regrouped his infantry units scattered across southern Pennsylvania. opposed only by weak Union militia, the Confederates had seized all of the livestock, food, clothing, and shoes they could find, while levying tribute on the towns. Advance elements were threatening Harrisburg when Lee ordered a concentration at Cashtown, 8 miles west of Gettysburg. On July 1st, a Confederate brigade, seeking shoes, engaged Union cavalry west of Gettysburg, a village where 9 roads crossed.
For 3 days, the armies grappled in battle. The Union defenders, assailed on both flanks and in the front, clung to their strong natural positions. The 2 armies suffered more than 50,000 casualties. On the 4th, lee began his retreat, crossing back into Virginia on the 14th.
The Gettysburg Campaign has been the focus of more study than any other Civil War engagement. Controversies surround the battle. Stuart's ride, the earlier death of Jackson, the inefficiency of Confederate staff work, Lt. Gen. James Longstreet's reluctance to fight offensively, Ewell's indecisiveness on July 1st, and Lee's belief in the invincibility of his army have all been argued as the causes of the Confederate defeat. Meade's battlefield generalship and the defiant valor of his veterans had much to do with the outcome. The Union victories at Gettysburg and Vicksburg were the military turning points of the war. The Confederacy had begun an inexorable descent toward defeat.