It's kinda hard to explain but I found a reliable website
http://www.history.com/topics/mcculloch-v-maryland
This i do not know sadly but i did some research for you and google says and i quote
"When Virginia declared its secession from the Union in April 1861, Lee chose to follow his home state, despite his desire for the country to remain intact and an offer of a senior Union command. During the first year of the Civil War, Lee served as a senior military adviser to Confederate President Jefferson Davis".
Edward P. McCabe (October 10, 1850 – March 12, 1920), also known as Edwin P. McCabe, was an African-American settler, attorney, and land agent who became one of the first African Americans to hold a major political office in the American Old West.