It appeals to lawfully appointed men to give themselves in the service of their calling. Lesser magistrates are in the front lines, then, according to Calvinistic thought, and upon them God has placed the burden to provide leadership against wicked higher-ups. It s not a very pretty picture. One lawful alternative is secession, i.e., removing oneself from the domain of the godless and binding oneself to a more righteous people. In Germany, Poland, France, etc., during the War, that might have meant people uniting themselves, formally and informally, with the underground, or the resistance, which functioned as if a country within a country, in league with allies without the country.
Peaceful secession is a very, very attractive position.
I would encourage our ethicists to fully discuss this very pertinent issue, perhaps in the pages of the Christian Renewal, and I thank you for bringing up this very Good Question.