On the issue of slavery, how were northern states as guilty as southern states?

yes they still had slavery even if you stoped sooner does not mean you did not do something bad

in 1897, pershing became a tactical officer at west point, and that's where he was given the nickname "black jack." pershing's first name is "john," for which "jack" is a nickname, and he was a white man who commanded black troops. hence "black jack".