Final answer:
Lee decided to attack the center of the Union forces at Cemetery Ridge on July 2 using a tactic known as Pickett's Charge; the goal was to break the Union defensive line.
Step-by-step explanation:
On July 2 during the Battle of Gettysburg, Confederate General Robert E. Lee decided to attack both flanks of the Union forces positioned along Cemetery Ridge. After his attacks on the Union flanks ultimately failed, on July 3, Lee made the determination to concentrate his efforts on the Union center in what would become known as Pickett's Charge.
He ordered Lieutenant General James Longstreet to orchestrate the middle attack, and Major General George Pickett was chosen to lead the assault. The purpose of this military maneuver was to break the Union's defensive position at the ridge, though it was a classic military move that would not surprise Union General George Meade, outside of the specifics of timing and leadership.