Battle of Gettysburg
The nature of the result of the Battle of Gettysburg has been the subject of controversy for years. Although not seen as overwhelmingly significant at the time, particularly since the war continued for almost two years, in retrospect it has often been cited as the "turning point", usually in combination with the fall of Vicksburg the following day. This is based on the observation that after Gettysburg Lee's army conducted no more strategic offensives—his army merely reacted to the initiative of Ulysses S. Grant in 1864 and 1865—and by the speculative viewpoint of the Lost Cause writers that a Confederate victory at Gettysburg might have resulted in the end of the war.
It is currently a widely held view that Gettysburg was a decisive victory for the Union, but the term is considered imprecise. It is inarguable that Lee's offensive on July 3 was turned back decisively and his campaign in Pennsylvania was terminated prematurely (although the Confederates at the time argued that this was a temporary setback and that the goals of the campaign were largely met). However, when the more common definition of "decisive victory" is intended—an indisputable military victory of a battle that determines or significantly influences the ultimate result of a conflict—historians are divided. For example, David J. Eicher called Gettysburg a "strategic loss for the Confederacy" and James M. McPherson wrote that "Lee and his men would go on to earn further laurels. But they never again possessed the power and reputation they carried into Pennsylvania those palmy summer days of 1863."
Jonathan Letterman
The greatest casualties for his army were suffered at the three-day Battle of Gettysburg in July 1863, but it also showed the efficiency of Letterman's system, since while the mortality rate of the Army of the Potomac had been 33% during 1862's Peninsular Campaign, the mortality rate after this bloody three-day battle was only 2%, although no official report of the battle mentioned Letterman's contribution. To deal with more than 14,000 Union wounded, along with 6,800 Confederate wounded who were left behind, a vast medical encampment was created northeast of Gettysburg off the York Pike on the George Wolf farm, named "Camp Letterman." Of the Battle of Gettysburg and his system for treating casualties, Jonathan Letterman on October 3, 1863 reported to Brig. Gen. S. Williams, A.A.G., Army of the Potomac, "Surgeon John McNulty, medical director of that corps, reports that 'it is with extreme satisfaction that I can assure you that it enabled me to remove the wounded from the field, shelter, feed them, and dress their wounds within six hours after the battle ended, and to have every capital operation performed within twenty-four hours after the injury was received.' I can, I think, safely say that such would have been the result in other corps had the same facilities been allowed—a result not to have been surpassed, if equaled, in any battle of magnitude that has ever taken place.'" Maj. McNulty, the Medical Director of the XII Corps (Union Army), either "had not received" or more likely had outright disobeyed orders to leave behind medical baggage wagons and, therefore, unlike many other Union medical commanders at Gettysburg had sufficient medical equipment and supplies to adequately implement Letterman's systems at Gettysburg for the XII Corps.