I think it is unlikely happen so suddenly (I like the show btw) - the way it is described in the show it seems to happen within months, I can't see why it would happen quickly since the Governments and military are still technically in place and there are not mass casulties either from the blackout so although there is no power, there is still no reason for everyone to descend to anarchy so quickly and Governments to disappear and new militia to be warring within a short period of time
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