your commandments!!

[T-oddity]

Good question, personaly I would go for an elected leader, important to have some one able to lead from the front, to make quick and decisive decisions in emergency/life threatning situations. A senate of elected representatives to represent families and smaller groups within the community and a free and open forum for all members of the community regardless of age.
Banishment would be the ultimate punishment, though dependant on the situation and circumstances anything is possible a banished individual could become a future enemy and threat to the community.
What I fear is that what will actualy come about post shtf is that "might will be right" and it will be he who holds the biggest stick that will rule this has so often been the case throughout human history.