How were confederate leaders treated under the radical reconstruction plan?

Answer: confederate leaders could not hold public office

Explanation: The radical reconstruction plan among other things, listed as a requirement the prohibition of former Confederates from ever holding public office.

The Radical Republicans believed that the South should be dealt with harshly. They opposed Lincoln's plan, because they thought it was too soft and they opposed Johnson because they believed he sympathized with the South too much.

Lincoln's plans included granting amnesty to any southerner if he/she would pledge loyalty to the Union, with the exception of the confederate leaders while Johnson's plan, after Lincoln's assassination was to grant amnesty to former Confederate leaders as well, if they appealed to the president.