What's The Intent of Social Security?

Apropos of this soundbite over at Eschaton:

I really don't think the Catfood Commission gives two shits about raising the retirement age 40 years from now. What they're really after is means testing Social Security. If that happens, 40 years from now Social Security will be little more than a welfare program for the elderly.

Wasn't that always the general intent?

Seriously though, I feel like the discussion of Social Security is a little incoherent. Is Social Security a form of enforced retirement savings, or is it a form of social insurance? The history of Social Security strongly suggests that it's the latter, a stance echoed by previous posts at Eschaton.

If Social Security is an entitlement, part of the social safety net, then it makes sense to me that it should be means-tested. People who already have sufficient means don't need additional support nor do they, under the idea that making Social Security contributions is part of the general social contract, have any sort of moral claim to unpaid funds.

The alternative interpretation is that means-testing Social Security benefits is unacceptable because individuals have a moral claim to their contributions. If that's the case then Social Security is little more than a scheme to force people to save for retirement. In which case I'd like my taxes back; I'm quite capable of saving for my own retirement thankyouverymuch.