The Dahlgren affair was an incident during the American Civil War which stemmed from a failed Union raid on the Confederate capital of Richmond, Virginia in March 1864. Brigadier General Hugh Judson Kilpatrick and Colonel Ulric Dahlgren led an attack on Richmond to free Union prisoners from Belle Isle and damage Confederate infrastructure.
The attack failed and Dahlgren was killed while in retreat during the Battle of Walkerton. Papers discovered on his body revealed orders to free Union prisoners from Belle Isle, arm them with flammable material, torch the city of Richmond and assassinate Confederate President Jefferson Davis and his cabinet.
The papers were published in the Richmond newspapers and sparked outrage in the South with speculation that President Abraham Lincoln had given the orders himself. An angry mob disinterred Dahlgren's remains and disrespectfully placed them on display in Richmond. Reports of the mistreatment of Dahlgren's corpse inflamed public opinion in the North. Union newspapers and Dahlgren's father, Union Navy Rear Admiral John A. Dahlgren claimed the papers were a forgery. Union Major General George Meade had to personally assure Confederate General Robert E. Lee that the orders were not authorized by the Union Army. The controversy may have contributed to John Wilkes Booth's assassination of President Lincoln.
It has never been determined if the papers were forged or if not, who they were written by, although historian Stephen W. Sears points to the "unscrupulous" Secretary of War Edwin M. Stanton as the authority behind the plan to have the freed Richmond prisoners commit arson and assassination. Captain John McEntee of the Bureau of Military Intelligence, who accompanied Dahlgren on the raid, told General Marsena Patrick that the published documents were accurate, as they corresponded with what Dalhgren told him. This was confirmed by another B.M.I. agent, John Babcock.
After the war, Stanton requested the documents from Francis Lieber, who had been tasked with accumulating and preserving captured Confederate documents. Lieber was ordered to give them to the Secretary of War, and they were never seen again.
Background
In the winter of 1863-1864, Confederate prisoner camps such as Belle Isle and Libby Prison had become dangerously overcrowded due to the Confederacy's refusal to include captured black Union soldiers in the Dix–Hill Cartel exchanges of prisoners with the North. It was estimated that 1,500 Union soldiers were dying each month in Confederate prisons.
Spies reported that the Confederacy had very few men guarding the capital of Richmond and Brigadier General Hugh Judson Kilpatrick received approval from Secretary of War, Edwin M. Stanton, to launch an ambitious cavalry raid against Richmond. Kilpatrick had a reputation for recklessness which earned him the nickname "Kill-Cavalry". Kilpatrick recruited Colonel Ulric Dahlgren to assist in the attack. Dahlgren had lost a leg after being wounded at the Battle of Gettysburg and was eager to return to action after his recovery.
Kilpatrick-Dahlgren raid
Kilpatrick and Dahlgren led the operation to attack Richmond, Virginia; rescue Union prisoners from Belle Isle and damage Confederate infrastructure. The operation is also known as the Battle of Walkerton.
On February 28, Kilpatrick and Dahlgren left from Stevensburg, Virginia. Kilpatrick was to attack Richmond from the North with 3,500 men and Dahlgren from the South with 500 men. Snow, sleet and rain from an unexpected winter storm slowed the attack.
Dahlgren's forces were led to a ford on the James River near Dover Mills but were unable to cross due to high water from recent rains. Dahlgren redirected his troops to attack Richmond from the East. They heard the sound of battle and rushed to support Kilpatrick but ran directly into a Confederate Home Guard force which halted their advance. Dahlgren retreated East in an attempt to connect with Kilpatrick's force.
The Union troops were continually harassed by Confederate forces during the retreat and became separated. On the night of March 3rd, Dahlgren and a portion of his troops were ambushed near King and Queen Court House by 150 men in the Virginia cavalry under the command of Lieutenant James Pollard. Dahlgren was shot by four bullets and died on the battlefield. Several other Union soldiers were killed in the ambush and 135 were captured.