Resistance and the Magdeburg Confession

Topic Suggestion/Request:
* Disclaimer: This is a hypothetical question for theoretical discussion only (feel free to remove if needed)

I believe in the episode on the Magdeburg Confession you guys said that the general principle is that when the leaders of the populace are leading the populace into deliberate sin, then resistance is permitted (I apologize if this paraphrase is incorrect). Is there a certain level of egregiousness of the sin committed by the leaders (and/or of which they persuade the citizenry to commit) that is required in order for armed resistance by the citizenry to be justified? If so, can you further define what that level is?