The President of the United States can order the army into battle. He is known as the Commander in Chief.
The Union Army din't destroy Lee's Army. TAK3 TH15 L1F3!
Washington, Grant and Eisenhower are a few.
President Herbert Hoover
Ulysses Sympson Grant who, at the time of the battle of Third Battle of Chattanooga was the commander of the Union Army of Cumberland and that of Tennessee, which fought that battle.
1948.
President Lincoln saw the Confederate retreat back to Virginia after the Battle of Antietam as an opportunity to severely damage the Confederate army in Virginia. He urged General McClellan to rapidly pursue Lee's army into Virginia and cut his lines of communication with Richmond. This would force Lee into another battle with the Army of the Potomac and suffer a defeat due to Lee's smaller army. This would then leave Richmond ripe for a take over.
It was after the Battle of Antietam. McClellan had a perfectly good opportunity to pursue and destroy Lee's army while it was in a vulnerable position, but he moved far too slowly, and Lee was able to get his army back to Virginia.
He knew Grant would do anything to win the war.
He fled the battlefield as soon as he understood that he is loosing the battle in order to prepare a new army to defend his sovereignity at the battle of Gavgamela.
The invading army at the Battle of Hastings was the Norman army. It was led by the winner of the battle, William the Conqueror.
In very general terms it was the Confederate Army of Mississippi against the Union Army of the Tennessee. On the second day of the Battle the Union Army of the Ohio had arrived and joined the fight. An "Order of Battle" is a list of all units within a particular command at a certain date, or in a battle. See the "related links" below for complete Union and Confederate Orders of Battle.
George McLellan. The delays were so serious that some doubted his loyalty.