These seditionists are not in the military.
There is precedent for trying civilians for treason in military courts, and executions have resulted. And you might want to examine two recent events which are related to this subject:
1. Sen. Lindsey Graham's questioning of Judge Kavanaugh about the jurisdiction of military courts and the applicability of the UCMJ to civilians charged with treason. Judge Kavanaugh's clear agreement on the subject was eye-opening. (Skip to 25:50 on the YouTube video).
2. Recently published changes to Manual for Courts Martial which become effective January 1, 2019. These changes clarify the joint roles of the Secretaries of Defense and Homeland Security and the Attorney General regarding jurisdiction of military courts.
I believe there are too many convergences to be coincidental. We shall see...