"Carpetbaggers", epithet used in the South after the Civil War to describe Northerners who went to the South during Reconstruction to make money (source either google sources...just type it in...or the encylopedia).
Read the writings of Alexander Stephens for a start. In his Cornerstone speech he is quite insistent that slavery was the cause of the rebellion. In his diaries written while he was in custody after the war he seems to have changed his tune. Read the Declarations of the Causes of Secession or the speeches delivered to the various secession conventions. Over and over and over again a single theme runs through them all, defend slavery. Protect slavery. Accept Lincoln and you accept freedom for blacks and an end to slavery. The understanding that defending the institution of slavery from the threat posed by the Republican victory was by far the single most important reason for the southern rebellion has nothing to to with revisionist history. It doesn't come from the carpetbaggers, it comes from the speeches and writings of the men who led the rebellion. Slavery was their reason for rebellion, not mine.