John Alexander McClernand has been described by one biographer as “brash, energetic, assertive, confident, and patriotic”, but also as ”ever the politician.” As such he was given to frequent communications with his fellow politicians (in particular with the President), something that infuriated his fellow military officers who had to take orders from those same politicians. In a way John McClernand was Lincoln's dopplganger, and would end his life not far from where Lincoln himself would rest.
and used it as a springboard to first the Illinois statehouse in Springfield - like Lincoln - and later the U.S. House of Representative - like Lincoln. But where Lincoln came to believe in his own vision, McClernand was a more politically astute and even more ambitious. He was a Stephen Douglas Democrat, a strong union man and, as such, politically valuable to Lincoln...if he could be controled.
In 1860 McClernand resigned from congress and raised a brigade of men in Illinois to fight for the Union. He was commissioned a brigadier
General of Volunteers in May of 1861. At Fort Donelson and at Shiloh (both times under Grant) he displayed at best moderate skills in command, but extraordinary ambition, campaigning even while campaigning to replace both Grant and George McClellan, then commander of the Army of the Potomac. In October 1862 he convinced Lincoln to let him raise troops for an independent command against Vicksburg, and in January of 1863 he managed to use not only his own
13th Corp but to also commandeer Sherman’s and McPherson’s corps and Admiral Andrew Footes’s River squadron for operations against Arkansas Post, an outpost of the Vicksburg defenses. The operation was a
success but all three officers warned Grant that they considered McClernand unfit for command. The problem was, thanks to Lincoln’s political need for McClernand, no in the theatre outranked McClernand – except Grant. So, from this point forward Grant’s headquarters stayed as close to McClernand as possible. Which is why McClernand's Corp is always in the lead, during this campaign.

