Final answer:
The Confederate victory at the First Battle of Bull Run had immediate strategic advantages, encouraging negotiations and emphasizing their defensive position. Over time, however, the Union's superior resources and strategic gains, such as control over the Mississippi River and victory at pivotal battles, turned the tide in their favor, leading to the Confederacy's ultimate surrender at Appomattox.
Step-by-step explanation:
The First Battle of Bull Run was a significant event in the American Civil War, resulting in a Confederate victory. This outcome had considerable strategic implications for the Confederacy. It bolstered Confederate morale and convinced many leaders, including those from the Iroquois nation, that it was an opportune time to negotiate with the Union from a position of strength. The victory underscored the Confederacy's ability to wage a defensive war, utilizing their knowledge of local terrain, civilian support, and expanded resources from the Upper South states.
However, as the war progressed, the anticipated short conflict elongated into a grinding war of attrition. The initial Confederate advantages such as skilled military leaders, rough terrain knowledge, and support on the home front were challenged as the Union imposed blockades and gained victories in crucial battles like Gettysburg and Vicksburg.
Mass mobilization was a key turning point, as the Union was able to leverage its superior manpower and industrial capacity. The Union's strategic advantage grew as it took control of critical areas like the Mississippi River, leading eventually to General Lee's surrender at Appomattox Court House—effectively ending the war in favor of the Union.