This poem, which was written in January of 1862, laments the apparent inability of Union General George Brinton McClellan to do anything with the Army of the Potomac besides drill it and prepare it for battles that somehow never got fought. When Little Mac failed to press the advantage gained by fighting the Army of Northern Virginia to a draw at the Battle of Antietam in September 1862, President Abraham Lincoln finally had his fill of McClellan's "slows" and sacked the "Young Napoleon."
The "Stanton" mentioned in the final verse is Edwin Stanton, who replaced Simon Cameron as Secretary of War in 1862. "Jomini" refers to Antoine Henri Jomini, a Swiss military analyst whose studies of the Napoleonic campaigns were standard fare at the United States Military Academy. (McClellan, an 1846 graduate of West Point, enrolled by special permission at the age of 15 and graduated second in his class.)
Thanks to Dennis Maggard for finding this poem.