[killjoy]

The last hanging for federal treason probably occurred before 1783. In one example, Sgt. Thomas Hickey was executed for treason by Washington's army on June 28, 1776.

Wow! No wonder I couldn't find it. Looks like we are going to have to update the history books soon.

[Fledermaus]

I read, though, that the last time we executed a soldier for battle field action like Ackbar was in WWII before they created the Military Justice system.