The same logic that keeps the US in Iraq is going to keep Russia in Georgia.

They're going to say "We want to pull out, really we do, but we can't yet. The situation is just too volatile, and by pulling out, we'll only make things worse."

Armed militias would be a real problem if Russia just abruptly removed the spear from the wound this evening and didn't look back. There have got to be TONS of S.O. fighters who are just aching for some payback (most reports indicate that this is already taking place), and with most of the Georgian guns having retreated to the capital city, there's nothing stopping them from running roughshod over the country.