Conservatives say they don't believe in evolution, but act like they do (in the sense they tolerate "animal spirits" in economics, a sexual division of labor, and racial disparities which may be genetic in origin). Liberals say they believe in evolution, but act like they don't. And our most destructive policies happen at the intersection of these two forms of hypocrisy.

A runner-up: "social security" is not the exact nature of the problem we face. Instead, the problem is the dependency ratio: old people can live off of million-dollar 401K portfolios and the proceeds from selling million-dollar houses, or live off of social security--in either scenario, the working population will be forced to accept lower available consumption (and low returns on their savings) for a given level of income.