With Lieutenant General US Grant using his Overland campaign against the forces of General Lee, Grant wanted to insure the safety of Washington DC. Grant's plan was to have Major General Franz Siegel to join forces with Brigadier General George Crook who was advancing from West Virginia. Together, there would be 15,000 troops. Grant believed that these combined infantry forces plus a large cavalry force was enough to discourage Confederates in the Shenandoah Valley from menacing Washington DC.
Confederate General Jubal Early tried to relieve the siege pressure that Union General US Grant was placing on Petersburg. He led a raiding party of sorts north to Pennsylvania, which did little to change the war, however, it did cause US Grant to prevent any Confederate operations on Washington DC, by sending troops north to help reinforce the Union capital.
In the Spring of 1864, General US Grant knew he would have greater success against General Lee if Grant could damage Lee's supply lines from the Shenandoah Valley. With this in mind, he expected General Siegel to not only prevent a Confederate threat to Washington DC, but to also end the food supplies in the Shenandoah Valley that Lee was using.
Confederate General John Bell Hood had replaced General Johnston in order to prevent the fall of Atlanta. He was not successful and General Sherman had the city basically under siege. To save what was left of his army, General Hood had to evacuate Atlanta and Sherman marched in unopposed.
The Battle of Spotsylvania took place because General Grant wanted to move past General Lee and the Confederate army's right flank. His ultimate goal was to prevent General Lee from getting to Richmond and he chose Spotsylvania as the place to prevent this from happening.
The main and immediate concern of General Robert E. Lee on September 14, 1862 was to prevent George B. McClellan from smashing through the division of D.H. Hill at Turner's Gap. This placed Confederate General James Longstreet's divisions to be unable to be concentrated for the defense of Boonsboro.
One of the tasks given to General Franz Sigel by General Grant in 1864 was to advance down the Shenandoah Valley and prevent Southern forces from moving north and to pose a possible threaten Washington DC. General Sigel had been a " political general " with not enough experience to do the job. He failed to link up as planned with other Union forces and was defeated by Confederate General John Breckinridge at the Battle of New Market. He was replaced shortly thereafter by General David Hunter.
After the fall of Vicksburg, Jefferson Davis was outraged at Confederate General Joe Johnston. Davis blamed Johnston for his failure to prevent the capture of Vicksburg. Davis issued to Johnston a fifteen page letter that accused him of interpreting orders to suit his own ideas and for making excuses as to why Vicksburg could not be saved. Johnston replied to Davis on each point of criticism.
the site of surrender of the Confederate general Lee to Union general Grant in April 1865, marking the end of the Civil War, his surrender prevent several more years of Guerrilla War, Grant was lenient- the idea of reconciliation not vengeance, the south could keep its horses and the generals could keep their guns
To prevent the succession of the Confederate States.
The capital of the US. during the Civil War remained Washington DC, just as it was during the outset of the war. However, Abraham Lincoln had to declare martial law in Maryland to prevent the state from seceding and joining the Confederacy. That would have left his capital surrounded by hostile territory and probably would have forced the US. government to relocate.
Richmond was evacuated by the Confederate Government only about a week before Lee surrendered at Appomattox Courthouse.
1. The union General Patterson was supposed to occupy Confederate general Johnson in the Shenandoah Valley to prevent he joining Beauregard. But a few confederate outposts made lots of noise to occupy Patterson, while Johnson's men marched to Manassas. Their arrival, together with the brave stand of the Virginians under Thomas Jackson turned the tide battle.They lost it because the were under-trained and overconfident.