A “MANDATORY SAVING FLOOR”

The term “mandatory saving floor” caught my eye in the abstract for a paper titled “Getting Americans to Save: In Defense of (Reformed) Tax Incentives.”  I didn’t have time to read the paper, but I’m curious what the author, a tax professor at a major law school, meant by that.  Is he proposing mandatory retirement account contributions for all wage earners?  That’s an idea that’s been around for a while, but I think there are serious questions about its viability.  Anyway, isn’t that essentially what the social security tax was meant to be?