I say "voluntary" because from the first Guiteau rejected him and vilely abused him, vociferously insisting upon being his own lawyer.
From the moment Guiteau entered the trial room it was a theatrical extravaganza.

He was in irons, sandwiched between two deputy sheriffs, came in shouting like a madman, and began at once railing at the judge, the jury and the audience.

A very necessary rule had been established that when he interposed, whatever was being said or done automatically stopped.

Then, when he ceased, the case went on again as if nothing had happened.
Only Scoville intervened between me and Guiteau and I had an excellent opportunity to see, hear and size him up.

In visage and voice he was the meanest creature I have, either in life or in dreams, encountered.
He had the face and intonations of a demon.