I don’t think it quite works like that - in other words just based on the charges.
The only reason that military personnel are subject to the UCMJ is that they sign an enlistment contract or take an officers commission which specifically requires they subject themselves to the UCMJ instead of civilian courts. For good reason - as there are aspects of military life and the miilitary’s purpose (ie warfare) which do not work in civilian courts.
Note that for non-UCMJ offenses military personnel are still subject to civilian courts (traffic citations, etc) and can be tried for the same issue in both state and military courts (but not military and federal courts).
From this link: https://www.lawfareblog.com/military-jurisdiction-over-civilians-why-supreme-court-should-grant-cert-ali
“Prior to 2006, the UCMJ had authorized military trials for civilians “serving with or accompanying an armed force in the field,” but only during “time of war.””
“In 2006, Congress expanded that authorization to also allow such trials during a “contingency operation,” which federal law defines as virtually any overseas deployment (and some domestic ones) where troops are or may become involved in operations against an “enemy of the United States or against an opposing military force.””
That article also gives examples of civilian contractors tried since the change in 2006 and notes that there is a limitation for this on host country nationals that is in place through the MEJA
Finally only military courts have express authority over military crimes. What I have found is that this includes mutiny and sedition; but not treason or espionage.
The only questions for me then would be:
a) Do the crimes in question fall under the sedition exclusivity for military courts? Sedition for me means: overt conduct, such as speech and organization, that tends toward insurrection against the established order. Sedition often includes subversion of a constitution and incitement of discontent towards, or resistance against established authority. The subversion of the constitution piece would be the main focus of concern here. Typically the military uses this charge for disruption of good order and discipline, but it is a rare charge. Usually “failure to follow/obey lawful orders” gets the most usage.
b) Could the individuals as part of taking their oaths or holding certain positions have agreed to fall under the UCMJ for certain aspects of their duties or certain charges? I could see where the Secretaries of defense, army, navy, etc and the President would be in the chain of command and subject to the UCMJ - I just don’t know if that is formalized. What about the rest of the cabinet? Not sure.
c) Did any of the acts occur “In Theater” or within an operational zone?
I would instead see illegal contact with a foreign national as violations of espionage, treason, and/or the Logan Act. All can be tried in civilian courts and cover the acts you noted. Again for me the question is did they rise to subversion of the Constitution and the definition of Sedition. In that case it could be taken into military courts as I understand.
For any of those better versed in the legal parsing - please chime in.
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