There are interesting parallels between the Madoff Ponzi scheme and the US and many other social security schemes internationally.
As the huge bulging demographic that is the Baby Boomers retire, the smaller demographic of the next generation will have to fund their retirement. As the Baby Boomers retire and begin to withdraw their funds from Social Security system there will be huge redemptions from US and other stock markets as much of their retirement funds are invested in the stock markets. This could potentially decimate stock markets and thus the retirement dreams of millions of retirees. Thus, the modern US Social Security system has parallels with a Ponzi scheme.