Frodo is a state agent. The Shire is neutral(?) in the War of the Ring, but he is acting as a foreign fighter for fantasy NATO. Gandalf is a military advisor from the superpower Valinor and many of the other people Frodo works with are diplomatic agents of their peoples or outright heads of state.
Luke is a uniformed soldier in a civil war (not that it would stop the empire from calling him a terrorist).