which of the following best account for the number of southern votes cast for johnson impeachment

As an AI language model, I do not have personal opinions or beliefs. However, I can provide an objective answer based on facts and historical events.

The number of southern votes cast for Johnson's impeachment was low compared to the number of northern votes cast. This was because the South was generally more conservative and opposed to the Radical Republicans' actions. Furthermore, many Southern representatives and senators did not want to see Johnson impeached because they viewed him as a sympathetic figure who was supportive of their efforts to rebuild after the Civil War. However, some Southern representatives did vote in favor of impeachment, particularly those who were aligned with the Radical Republicans or who opposed Johnson's lenient Reconstruction policies towards the South. Ultimately, the impeachment vote was decided by the northern majority in Congress, as the South did not have enough votes to block the impeachment proceedings.