> Besides, it doesn't have to be perfect. It's enough that it renders a good chunk (say 20-60%) of the population useless job wise to have adverse effects.
Ya - within the US at least (current unemployment around 3%?), it does not even have to be at 20 - 60%. My feeling is that even 10 - 15% unemployment or below living wages would lead to revolts, especially if the unemployment is somewhat geographically concentrated.