The ethnic strife in Georgia is the most important lesson for us to learn from this conflict. Russian "militias" sweep in after the army and deliver various attacks on various civilians targets. In short, once civil authorities are hamstrung by invasion, the local people vent their built-up ethnic hatreds on each other, using the invasion as an opportunity to clear out the ethnic minorities.
Militias, meaning armed and cohesive groups of civilians, rule the day. Americans, take note!