General Longstreet tried to dissuade him, pointing out it would be far better to leave and go around the union army to take up a position atop a hill closer to Washington, and let the union army beat itself to death attacking them.
Easier said than done. Recall that Lee had been rendered blind up until contact by the absence of his cavalry, as a consequence Lee was necessarily reacting to events, not driving them and the far flung Army of Northern Virginia was still assembling upon Gettysburg throughout the first two days of the battle. Other than those he could actually see, Lee could have no knowledge of where other Union forces might be deployed in the area.
It was too late to follow Longstreet's otherwise sound plan, Lee would have had to disengage his forces in the face of a rapidly gathering Union Army, communicate the new plan in detail to his still approaching units, and then march 60,000 men undetected around the left flank of that Union Army.
The most likely outcome being that Lee would have been attacked while in column, which woulda been a whole different battle, and prob'ly not a good one for the Confederates.
JMHO
