How did McClellan's and Grant's strategies vary when capturing Richmond?

To the excellent answers here, I would add that Grant's core strategy (independent of specific troop movements) was to simply engage Lee, over and over, using the Union's overwhelming advantages in men and materiel to win by attrition.

McClellan attempted to win a war of strategic maneuver, and combined with his perfectionist personality this led him to continually refrain from directly engaging Lee, much to Lincoln's ongoing and documented frustration. Lincoln famously responded to criticism of Grant's casualty rate (after Shiloh) by insisting, "I cannot spare this man - he fights," in an implicit criticism of his other more cautious generals.

Grant understood that he could replace his losses, and Lee could not. By engaging the Army of Northern Virginia in a series of high-casualty engagements, at the Wilderness and elsewhere, he broke Lee's back without ever really outmaneuvering him. Grant's Richmond campaign eventually evolved into an early version of trench warfare - and as soon as it did, the South was doomed.

McClellan's Peninsula strategy required the Army of the Potomac to execute better than the Confederate Army of Virginia in many ways; something that it was never able to do over the entire course of the war. Advancing on a narrow front with only two small attempts to truly leverage his overwhelming command of the waves, McClellan's advance was repeatedly blocked without difficulty by Lee, until his forces were exhausted. Perhaps a better army or commander might have made the strategy work, but the strategy itself required superiority in more than just numbers to work. To paraphrase a great commander of a half century earlier, McClellan "came on in the same old way, and was beaten back in the same old way."

By way of contrast Grant truly leveraged his numerical superiority and tactical shortcomings by utilizing a much wider front of advance. Repeatedly pinning Lee with the bulk of his army, Grant could battle to a tactical draw, or even a small tactical loss, and continue sidestepping towards Richmond and St. Petersburg to force Lee into continued strategic retreats.

Napoleon coined this strategy Manoeuvre sur les Derrières, and it was his favourite. B. H. Liddell Hart called it the Strategy of the Indirect Approach and on page 166 notes:

.... And in justice to Grant, it should also be noted that if his approach was direct in the broad sense, it was in no sense a mere frontal push. Indeed, he continuously sought to turn his enemy's flanks by manoeuvre, if manoeuvre of a small radius. Further, he fulfilled all the military precepts about keeping his army well concentrated and maintaining his objective [destruction of Lee's army] undeterred by alarms elsewhere.

. Grant executed it masterfully, and achieved in only 6 weeks of early 1864 a situation that finally dispelled any illusion that the Army of Virginia had strategic options.

Question: How did McClellan's and Grant's strategies vary when capturing Richmond?

The two Generals, George B. McClellan and Ulysses S. Grant were very different as leaders of the Union Army.

What were the differences between their strategies when trying to capture the capital of the confederacy, Richmond, Virginia?

.

Short Answer:

McClellan's strategy(May 1862) was to capture Richmond and hopefully the Confederate Leadership as a stepping stone to winning the war. Grant's strategy(June 1864) was not to take Richmond and was less concerned with capturing the Confederate Leadership. Grant strategy was to force Lee to defend Richmond. To bottle Lee up there while Grant set about winning the war by subduing and occupying the rest of the South. When Lee ultimately escaped Grant's siege of Richmond after 9 months, the war was already over. The Confederate Leadership also escaped Richmond, on a train route which was left open to occupy Lee's army during the siege, and would be rounded up piece meal over the following few months after the fall of Richmond and Lee's surrender.

Detailed Answer:

General George McClellan

George McClellan graduated second in his class at the U.S. Military Academy, West Point, New York (1846), he served in the Mexican War (1846–48), taught at West Point (1848–51) and went to the Crimean war(1855–56) as a military observer to report on European military techniques.

.

McClellan was popular with his men who would refer to him as "Little Mac", or "Young Napoleon". He was a competent General who excelled at the minutia of war. He excelled at logistics, training, and preparation for battle. He was a great hero of the Union initially who rebuilt the Army of the Potomac after the disastrous defeat at the battle of first Manassas. McClellan also was obsessive in planning his maneuvers. If he didn't see a clear advantage he did not commit to battle. McClellan's biggest shortcoming was he often overestimated his enemies strength resulting in him exerting caution when he should have been on the offensive. McClellan was the perfect General to fight against the Confederate's cautious Major General Joseph E. Johnston. During the Peninsula Campaign McClellan's systematic attacks and advances were matched by Johnston's systematic retreat.

By the end of May 1862 Union forces were so close to Richmond they could hear the church bells from the center of the city. General Johnston is wounded (At the battle of Seven Pines) and is replaced as commanding General of Confederate forces. General Gustavus Woodson Smith takes command for a single day. General Smith has a nervous breakdown his first day of command and is followed by the Confederates great general, Robert E. Lee June 1, 1862.

(*) Honorable mention goes to Jackson's Valley Campaign. That's General Thomas (Stonewall) Jackson. He was able to engage and defeat multiple Union armies who's combined strength was significantly larger than his own forces and keep them from Joining McClellan on the outskirts of Richmond. Jackson did this by defeating his opposition "in detail". He avoided battle when the Union was massed, but when they were divided or stretched out and he had the numerical superiority he attacked with superior numbers. Jackson would fight six battles against a numerically superior Union Army, and have superior numbers in five of those battles, all of which he would win. Jackson thus was able to tie up 50,000 men which McClellan was counting on for his Richmond campaign. After defeating the Union forces in the Shenandoah Valley Campaign, Jackson joined with Lee in defeating McClellan in the seven day's battles.

Army of Northern Virginia: Temporary command under Major General G. W. Smith
Maj. Gen. Gustavus Woodson Smith commanded the ANV on May 31, 1862, following the wounding of Gen. J. E. Johnston during the Battle of Seven Pines. With Smith seemingly having a nervous breakdown, President Jefferson Davis drafted orders to place Gen. Robert E. Lee in command the following day, June 1, 1861.

. After Seven Pines, and Lee takes command McClellan wastes the initiative and gives Lee valuable time to plan his next moves.

General George McClellen
McClellan spent the next three weeks repositioning his troops and waiting for promised reinforcements, losing valuable time as Lee continued to strengthen Richmond's defenses.

.

Lee understood McClellan and turned his caution and obsession for planning against him. Lee overwhelmed McClellen, not with troops but with activity. Lee's first sent out units to harass McClellan and take away his confidence. June 12, 1862 JEB Stuart makes McClellan look like a fool. Stuart takes 1,200 calvary and circles McClellan's army of the Potomac consisting of 105,000 men. JEB Stuart's forces captured supplies and horses, and destroyed the primary depot and rail line supplying McClellan's army. In the absence of solid intelligence, McClellan was frozen when called upon to take spontaneous action. Stuart's forces were at all times no further than a few miles away from McClellan's troops, and yet McClellan was unable to think in the moment to defend his army from the fast moving opponent.

Next Lee would utilize this same technique on a larger scale, Seven Days Battles (June 25 to July 1, 1862). Six major battles in seven days. McClellan was denied time to plan, denied time to prepare. His forces were routed. By the end of the Seven Days Battles, McClellan's larger army had retreated from Richmond to the safety of the James River where they were safeguarded from Lee's smaller force under the guns of the Union's Navy. McClellan would never threaten Richmond again. Lee was on the offensive and moved into Northern Virginia and eventually invaded Maryland, all the while dictating Mcclellan's movements before him. Mcclellan would be replaced as commander of the Union Army in Nov 1862. At the time Lee would write to his wife, "I hate to see McClellan go". McClellan would stand unsuccessfully against Lincoln in the Presidential election of 1864. Mcclellan would run for President, as an active duty General in wartime, on the platform of immediate cessation of hostilities and a negotiated settlement with the Confederacy. (McClellan resigned from the army on election day).

General Ulysses S. Grant

General Ulysses S. Grant was a good tactician, but ultimately what won the war and separated Grant from those who came before him was his Strategy. He pursued Lee, and with his aggressive pursuit he forced Lee into untenable situations. Grant was promoted as commander of all Union Armies March 2, 1864. His first offensive May 4, 1864 would consist of 14 major battles over 2 months, the Overland Campaign. Grant didn't defeat Lee in all of those battles, Cold Harbor for example was a defeat for the Union ( 52,788 Union casualties, nearly twice what the Confederacy Suffered). Cold Harbor would earn Grant the nickname, the butcher, but Grant kept coming. Grant constantly pursued, engaged, and pressured Lee. Strategically the Overland Campaign systematically took away all of Lee's options. Grant forced Lee backwards and ultimately forced him to again commit his forces to the defense of Richmond (June of 1864). It became a 9 month siege, where Lee's forces contained in Richmond could not go on the offensive, take pressure off, or assist the rest of the Confederacy. Mobile Alabama fell(August 1864), The city of Atlanta falls(Sept 1864), and Sherman completed his march to the sea (Dec 21, 1864) creating a devastating swath across the Confederacy. During the siege Grant made Lee expand his defenses, stretching out his lines(32 miles) in an attempt to preserve the City's railroad and supply line. This left Lee's forces thin and committed to the defense, unable to mass or conduct offensive action.

After 9 months of wearing down Lee, Grant orders a general assault April 2, 1865. Lee breaks out of the siege, but ultimately has nowhere to go. Union cavalry under Sheridan cut Lee's retreating army off from his supply train, and the end was nearly at hand. April 8, 1865, six days after he breaks out of Richmond, Lee and Grant meet at Appomattox Court House to discuss surrender.

The Confederate Leadership escapes Richmond by rail April 2, 1865. Jefferson Davis the Confederate's President would be captured by Union forces May 10th, 1865 near Irwinville, Georgia; 600 miles south and 5 weeks removed from the fall of Richmond.

Sources:

• Peninsula Campaign
• Army of Northern Virginia
• Seven_Days_Battles
• Stuart's Ride
• JEB Stuart Rides Around the Union Army
• JEB Stuart's Wild Ride
• General George McClellen
• General Ulysses S. Grant
• Overland Campaign
• General Joseph E. Johnston
• Gustavus Woodson Smith
• Robert E. Lee
• Appomattox Court House
• Britannica George B. McClellen
• NY Times
• The Capture of Jefferson Davis
• Jackson's Valley Campaign