<P> Early in the war, Confederate strategists believed the primary threat to New Orleans would come from the north, and made their defensive preparations accordingly . As forces under Grant made gains in the Western Theater, much of the military equipment and manpower in the city's vicinity was sent up the Mississippi River in an attempt to stem the victorious Union tide . When Flag Officer David Farragut was able to force the Union Navy's West Gulf Blockading Squadron past the Confederacy's only two forts below the city in the Battle of Forts Jackson and St. Philip, New Orleans had no means to oppose capture . Thus the port, by far the largest Confederate city, fell undamaged into Union hands, tightening its grip on the Mississippi River and fulfilling a key element of the Anaconda Plan for the South's defeat . Although the occupation under Maj. Gen. Benjamin Butler was detested, he was astute enough to build a base of political support among the poorer classes and create an extensive intelligence and counterespionage capability, nullifying the threat of insurrection . The Confederacy's loss of its greatest port had significant diplomatic consequences . Confederate agents abroad were generally received more coolly, if at all, after news of the city's capture reached London and Paris . </P> <P> The Battle of Antietam, fought September 17, 1862, was the bloodiest single day of conflict in American military history . But it also had two strategic consequences . Although considered a tactical draw between the Army of the Potomac and the much smaller Army of Northern Virginia, it marked the end of Robert E. Lee's invasion of the North . One of his goals was to entice the slave - holding state of Maryland to join the Confederacy, or at least recruit soldiers there . He failed in that objective; he also failed in marshaling Northern fears and opinions to pressure a settlement to the war . </P> <P> But more strategically, George B. McClellan's victory was just convincing enough that President Lincoln used it as justification for announcing his Emancipation Proclamation . He had been counseled by his cabinet to keep this action confidential until a Union battlefield victory could be announced, lest it appear to be an act of desperation . Along with its immense effect on American history and race relations, the Emancipation Proclamation effectively prevented the British Empire from recognizing the Confederacy as a legitimate government . The British public had strong anti-slavery beliefs and would not have tolerated joining the pro-slavery side of a fight where slavery was now a prominent issue . This removed one of the Confederacy's only hopes of surviving a lengthy war against the North's suffocating naval blockade . Support from France was still a possibility, but it never came to pass . Antietam and two other coincident failed actions--Braxton Bragg's invasion of Kentucky (sometimes called the "high - water mark of the Confederacy in the Western Theater") and Earl Van Dorn's advance against Corinth, Mississippi--represented the Confederacy's only attempts at coordinated strategic offensives in multiple theaters of war . </P> <P> After winning the Battle of Chancellorsville, the Army of Northern Virginia lost Lt. Gen. Stonewall Jackson to pneumonia following a friendly fire accident . His death was a blow to the morale of the Confederate army, as he was one of its most popular and successful commanders . Two months later, Robert E. Lee had no general with Jackson's audacity available at the Battle of Gettysburg . Many historians argue that Jackson might have succeeded in seizing key battlefield positions (such as Culp's Hill and Cemetery Hill at the end of day one) that his replacements were unable or unwilling to take . Lee himself shared this belief and is said to have told his subordinate generals on different occasions that they should have acted like Jackson would have . </P>

Why did the civil war mark a major turning point in american history