From my earlier post:
Let me put the following scenario to you. A mafia boss, who coerces compliance with his wishes by force, has a set of "rules" that everyone in his region knows they need to obey, or they will suffer violence. The local government is incompetent and corrupt, often violating its own rules (i.e. its constitution), and the police force is unable to enforce the "official" law. Eventually, the government deteriorates to the point that it is unable to exercise authority, powerless to defy the mafia boss. No one votes in the elections, and no one pays attention or respect to the police. Finally, the mafia boss becomes the de facto ruler of his region, being the only one able to enforce any sort of order (via his "rules" and the violence he employs to assure compliance). He codifies his "rules" on paper and calls it the law. No one publicly disagrees, because they are afraid of suffering violence or being imprisoned.
So is the mafia boss now the right and lawful authority under God? Without him, there would be no "government," as the previous government is now just a toothless ghost of a government, lacking in all credibility and power. Has the mafia boss, who is now the higher authority with the backing of his own law, somehow obtained the status of "lawful authority under God"?
It would seem that the "mafia boss" now has the responsibility under God to exercise his authority for a good End.
However, this is something which would require a rather strong dissolution of the previous governing body. For example, most criminal organisations are able to exist (sometimes flourish) under another ruling body (the government). The fact that the government is corrupt or unwilling to protect its people is a failing in itself, but it does not dissolve the government immediately.
However, if you removed "mafia boss" and replaced it with a general term for a new government, then you'll find your situation is not only common, it is how new governments are formed all the time.
The use of violence (imprisonment, etc) in enforcing one's will is the mark of government.