Allan Pinkerton was hired by US General George B. McClellan for espionage work for confederate operations.
Lincoln fired several generals. He fired McClellan twice.
George McClellan
Lincoln's Democratic opponent in the election of 1864 was General George McClellan.
General Robert E. Lee.
George McClellan was born and raised in Philadelphia. When he became a major general in the army, he traveled and lived all over the US. He passed away in New York.
General McClellan was pleased by the change of Confederate command due to the wounded General Johnston. McClellan considered Lee to be meek and clearly was not chosen to lead any major Southern armies. Also, McClellan had a brief encounter with some of Lee's soldiers who failed to retain what would become West Virginia.
Confederate General Robert E, Lee and Union General George McClellan
general Robert E. Lee
George b McClellan was a Union general. All the generals do is command their troops.
Richmond, Virginia
McClellan's Peninsular campaign failed because the Confederate army was defending Richmond better that McClellan anticipated. They retreated, then turned and attacked McClellan, surprising the Union general.
Major General Nathaniel P. Banks reported to his commanding general in August of 1861, General George B. McClellan. Banks was in charge of the Department of the Shenandoah, with his headquarters being in Sandy Hook, Maryland. McClellan informed Banks that a Confederate offensive would begin shortly and Banks was ordered to report military operations to McClellan at least four times per day.
Lincoln was disappointed that General George B. McClellan had allowed Confederate general Lee to escape after the Battle of Antietam. The result of Lincoln's disappointment was the replacement of McClellan by General Burnside.
Confederate General James Longstreet was present at the meeting in Richmond where strategy was formed on the best way to counter the Union's attack on the Peninsula. Longstreet accurately predicted that because Union General George B. McClellan was an engineer at heart, he would not act rashly. Longstreet cautioned against making any rash moves against McClellan because the Union general was known to avoid heavy offensive operations. Therefore, prudent but effective defensive actions would slow down the battle cautious Union general.
Because Lincoln felt that McClellan lacked the aggressiveness required to successfully defeat the Confederate army. McClellan was very meticulous and patient. He did not chase Confederate General Robert E. Lee after defeating his troops at Antietam. Lincoln got tired of McClellan's patience and decided to replace him with Ambrose Burnside.
When Confederate General Joseph Johnston withdrew his forces near Washington DC southwards to protect Richmond, one huge opportunity for General McClellan vanished. McClellan had hoped the Rebel army would remain north of Richmond. Had that happened two favorable elements of his campaign were ended. McClellan's plan was to have a chance to attack Johnston's forces from the rear and he also had the chance to place his army between the Rebel army and Richmond.
General McClellan believed that landing his army at Urbana Virginia gave him his best chance to cut off the forces Confederates under the command of Major General John B. Magruder. The landing there would be a total surprise for the Rebels and enable McClellan to reach Richmond before he could reinforce the Confederate capital. Urbana had to be placed aside and McClellan had to chose Fort Monroe as his forward base of operations in that the uncertainty caused by the ironclad CSS Virginia at Hampton Roads.