So I don't know if anyone's made this connection yet (dayshift was too busy spamming twitter memes yesterday when Q brought it up) but the newly-created US Space Force is excluded from the restrictions of the Posse Comitatus Act. And according to the Air Force majors who wrote 'The Case for Space: A Legislative Framework for an Independent United States Space Force', the Space Force was created as a separate entity specifically to enforce US space laws, which would have been prohibited under the Air Force due to the Posse Comitatus Act.
So we have the Marines, working in conjunction with the Coast Guard (also excluded from Posse Comitatus due to being under DHS) and the Space Force. Which, in real life application, probably means pic related.
Here's the paper if anyone wants to read it. Posse Comitatus is gone over on pages 22-23:
>https://www.airuniversity.af.edu/Portals/10/AUPress/Papers/WF_73_GRANT_NEIL_THE_CASE_FOR_SPACE_A_LEGISLATIVE_FRAMEWORK_FOR_AN_INDEPENDENT_UNITED_STATES_SPACE_FORCE.PDF