If workers aren't happy with a pension that, while generous in relation to the living standards of their younger years, feels stingy in relation to their earnings immediately before retirement, they can, if not in the lower brackets, save privately to supplement their Social Security benefit; if healthy, they also can postpone retirement.
As Josh points out, just who the hell do they think they're talking about? There are 6 tax brackets, and the top 3 only kick in for about the top 10% (probably less) of the population. So, the Bush administration is planning to demolish social security, and, hey, unless you're part of 90% of the population you can "save privately to supplement" your benefit. If you are part of the 90% riffraff, well, I guess you're just shit out of luck?