When the Union Army occupied the city on May 1, Mumford was arrested and charged with "high crimes and misdemeanors against the laws of the United States, and the peace and dignity thereof and the Law Martial." On May 30 he was tried before a military tribunal and convicted, even though there was no clear attempt to determine whether the city was actually occupied when the event occurred.
On June 5 Butler issued the following Special Order No. 70:
William B. Mumford, a citizen of New Orleans, having been convicted before a military commission of treason and an overt act thereof, tearing down the United States flag from a public building of the United States, after said flag was placed there by Commodore Farragut, of the United States navy: It is ordered that he be executed according to sentence of said military commission on Saturday, June 7, inst., between the hours of 8 a.m. and 12 a.m. under the directions of the provost-marshal of the District of New Orleans, and for so doing this shall be his sufficient warrant.
Clearly Butler thought the sentence was for treason in the common sense of the word, but was the charge really treason according to the Constitution, namely
Treason against the United States, shall consist only in levying War against them, or in adhering to their Enemies, giving them Aid and Comfort.
Did the actual tribunal decision state that Mumford had performed an act of treason, as opposed to, say, disobeying the Martial Law (which he also did when he refused to follow an order not to tear down the flag.) Clearly the tribunal could have ruled that tearing down the flag gave Aid and Comfort to the enemy. But did the tribunal's decision actually say that?