Social Security theory

Matt Yglesias, writing at Talking Points Memo has a great little breakdown of the theory underlying Social Security. It's kind of an explanation and a defense at the same time, and well worth reading. Certainly, for an enviro like myself with little experience in social policy issues, I found it interesting. I don't know how much of what he describes was actually discussed when Social Security was initially set up, but it certainly sounds plausible now.