James F. Gibson, Panorama of McClellan's Army at Camp, 1862
George McClellan's colossal army of more than 100,000 soldiers threatened Richmond from the east in March 1862. Confederate General Joseph Johnston reluctantly challenged him. When Johnston was wounded, Lee replaced him in command. Lee had the ability and temperament to seize control of the situation. He would not just attack McClellan's army; he would try to obliterate it and thereby end the conflict in one stroke.
Photograph courtesy of the Library of Congress