I agree, and that is generally a good thing, but I also think there is a concern for militias that are no better than thugs. Not everyone is noble and wants to save their family/neighborhood.
Power corrupts . . . It is not unlikely that when the SHTF some militias will prey on the less armed.
In 3rd world countries they are called warlords.
True, but when authority fails, people will have to band together as a matter of survival. They will simply need to devise a defense from those very thugs you mention.
If we were to experience a truly catastrophic event, say an asteroid strike, or perhaps a multiple WMD hit by Islamic terrorists, it is possible or likely that we'd see a breakdown of our civilization.
With traditional authority gone, survivors will fill the vacuum one way or another. It may be with warlords, it may be with democratic socialism, hell, it may even be modeled on American tradition. But people *will* band together and create some form of authority and society for their own protection.
I believe that in the entire history of the world only one society, ours, has been purposely based and designed on a premise of individual liberty. The tradition of that premise means that some will, in case of such a catastrophe, endeavor to reproduce it. Hopefully, enough will endeavor to actually reproduce America.
OTOH, so much of our society, from the president on down, are abandoning our traditons that who knows what Phoenix might arise from the ashes of our civilization. And what happened here in the late 1700's was definitely a long shot.