What could be johnson’s reasoning for not further punishing confederate leaders? what arguments could be made for supporting the radical republican view of adding further punishment?

Radicals believed that the safest approach was for the North to be a sort of dictator to the South. They were afraid that unless southerners' treason was harshly punished, the nation could never unite in a trustful bond that would guarantee their loyalty.

Even though Johnson had been outspoken about a need to punish the South, he ended up extending a pardon to all former confederates who declared a promise to stand by the Union and obey laws against slavery. In addition, he let former confederate officials to occupy positions in state congress after the elections.

When President Johnson started vetoing all laws that protected former slaves and black people in the south, it was made clear that ultimately he was trying to preserve the status quo and white privilege, and wasn't as forward-thinking as radicals had thought.

Hope this helps!

i am sure the answer is d

“i think it is very plausible that if there are five votes to end the death penalty, it could be with the people who are on the court right now,” - smith

so basically it is not clearly and consistently imposed