Grant Under Fire, takes a revisionist view of the Battle of Shiloh, declaring it a strategic defeat for the Union. The text describes John Pope’s and Andrew Foote’s success at Island No. 10 on the Mississippi, and then remarks on how they were next aiming for Fort Pillow and Memphis, Tennessee. It concludes:
“Foote expected success within days. Just before the attempt, Halleck summoned Pope’s army to the Tennessee River due to Shiloh, indefinitely delaying Memphis’ capture. By the end of April, Farragut had taken his fleet past the forts guarding New Orleans, leading to its surrender and occupation by an army under Benjamin Butler, shortly thereafter. The Union, with its enormous naval power both above and below and its preponderant land forces, might have rapidly opened the [Mississippi] from end to end, but for Shiloh. In that respect, the battle represented a major strategic defeat, despite having been a tactical victory.”
Just the delay in capturing Fort Pillow and Memphis was costly, as Union possession of the Mississippi was a distinct possibility by mid-1862. And if Buell could have safely joined Grant, the Confederates might well have been ejected from Corinth sooner than they actually were. So, in my opinion, Shiloh represented a strategic defeat for the United States forces.