Probably the nadir of the Union war effort was reached by the Mud March of the Army of the Potomac which began 150 years ago on January 20, 1863. Desperate to redeem himself after the bloody fiasco at Fredericksburg the commander of the Potomac, General Ambrose Burnside, ordered an unusal winter offensive, planning to cross over the Rappahannock at Banks ford, .
The weather was unseasonably mild on the 20th. On the evening of the 20th-21st the rains began and did not stop. Burnside quick began throwing pontoons over the river, but as the landscape dissolved into a sea of mud, the progress of the Army slowed. Lee had ample time as a result to station the Army of Northern Virginia across from Burnside on the southern banks of the Rappahannock. Other than sharpshooter fire, Lee made no effort to stop Burnside from crossing, perhaps thinking that fighting Burnside with a swollen Rappahannock in the rear of the Army of the Potomac gave an excellent prospect of destroying the Union force.
However, Burnside did not cross. His army was effectively stuck in the mud, as noted by amused Confederates who posted a large sign reading “Burnside’s Army Stuck in the Mud”. Burnside gave up on the 23rd and began his retreat. In after years many Union veterans would recall the wearying mud march back to their encampments around Washington as their worst experience during the War. Burnside was finally sacked by Lincoln on January 26th. It was a great pity that the militarily talentless Burnside was not summarily dismissed from the Union Army, a fact would bedevil Grant during his Overland Campaign and the Siege of Petersburg, where Burnside would give fresh examples of the art of military incompetence.