I thought this was obvious. Further, as No_Name is an officer within the military, he is subject to military tribubal. What Graham more or less did was ask Kavanaugh how it would have played out if they attempted to challenge the use of a tribunal court to declare No_Name guilty of treason.
Effectively - they would have lost that, too… And that is also the precedent which gives them the authority to do what is coming, as well.
Effectively saying "heads I win, tails you lose."