Madoff was a voluntary Ponzi scheme and Social Security is involuntary

Is it Ponzi
if you can't get out?

From  Tim Carney of The Examiner, modifying the diagram by Nick Baumann of Mother Jones.  Tip of the hat to Ace of Spades who gives a tip of the hat to Veronique de Rugy (who says, "You're welcome") who gives the link to The Examiner.