Keep your crayons handy to use in that history book of yours.
From (Secession on Trial, Cynthia Nicoletti, Cambridge University Press, 2017):
"Johnson had promised to make treason odious, and he was determined that Davis's would be the first--and most important --prosecution." p.(33)
"The particular charge also related to the forum in which his case would be heard--military or civil. Davis's conviction was virtually assured if the trial were to be conducted in a military court, where the procedural protections of the Bill of Rights, including trial by jury, were suspended." p.(33)
"Stanton and Secretary of State William H. Seward emerged as Davis's most zealous opponents, arguing strenuously in favor of trying Davis before a military commission, primarily for his alleged role in Lincoln's assassination and secondarily for the crime of treason. Seward emphasized that a military trial was necessary, as he had no confidence in the proceeding before a civil court." p.(34)
"Seward was focused on achieving the right outcome. He insisted that Davis's trial had to be conducted before a military commission, before a jury of military officials, as there could be no conviction of such a man, for any offense, before any civil tribunal." p.(35)
"Postmaster General William Dennison maintained....Davis should face treason charges only in civil court, as a military commission could try only cases arising under the law of war." p. (35)
"Welles again argued emphatically for the civil court and an arraignment for treason...even if it meant that Davis would not be convicted." p.(35)
"James Harlan disagreed, believing it would be foolhardy to try Davis before a civil court unless satisfied there would be a conviction." p.(35-36)
"The cabinet was divided, and Johson would not act boldly on his own. The case was just too perilous...Attorney General Speed decided to move forward independently. When the cabinet consulted on the Davis matter on August 22, Speed announced that he had retained two well-known lawyers from outside his office to direct the treason prosecution. William M. Evarts of New York City, and John H. Clifford of New Bedford, Massachusetts, with Evarts taking the lead." p. (37-38)
The trial of Jeff Davis for treason would be held in civil court, not a military hanging court.
Quantrill