All legal. The last one is debatable but make them fight it out in court. You can just confiscate the weapons and release the soldier. You can do a lot of things. Do you think that governor DeSantis or governor Abbott would tolerate Joe Biden doing this? No, they would fight back.
As alarmed as people may be, they aren't alarmed enough. Trump just escalated this crisis from a fight between the federal government and a state, to a situation where one state is deploying armed forces to impose its will on another state. www.thebulwark.com/p/emergency-...