William A. Crafts, Life of Ulysses S. Grant: His Boyhood, Campaigns, and Services, Military and Civil.

[55] endeavoring to obtain an independent command. It was very desirable that the Mississippi River should be opened its entire length. The Union forces had opened it to Memphis and below, but at Vicksburg the rebels had strong fortifications, and entirely commanded the river between that place and Port Hudson, thus maintaining their communications between the west and the east, and drawing large supplies from Louisiana and Texas. McClernand proposed to open this part of the river, and persuaded President Lincoln to authorize him to organize a force of the new troops from the west for that purpose. He imagined himself fully equal to the undertaking, talked boastfully, claimed the expedition as his original conception, and desired the sole command, with the idea that he should have the sole honor of its success. General Halleck, however, and others, had no such exalted opinion of McClernand's abilities as an officer, and he was allowed to organize the expedition subject to General Grant's direction. Halleck seemed to have more faith in Grant than formerly, or at least placed him far above McClernand as a soldier. He atoned for his former injustice by allowing Grant great freedom of action, and heartily aiding him in all his plans.

But McClernand had no patent right to such a movement. It had formed a part of Halleck's grand plan of operations when he was commander of the Western Department; and Grant had long ago had his eye on Vicksburg as an objective, towards which he would have advanced had his forces been sufficient. Before McClernand got ready to take command of his expedition, Grant sent Sherman, with all the troops collected