> I'm not sure I understand the mechanics behind this point of view. Here's the definition of Ponzi scheme from Wikipedia: "A Ponzi scheme is a form of fraud

> I'm not sure I understand the mechanics behind this point of view. Here's the definition of Ponzi scheme from Wikipedia: "A Ponzi scheme is a form of fraud that lures investors and pays profits to earlier investors with funds from more recent investors." Social security operates in the same way. It pays earlier investors (old people) with funds from more recent investors (young people). Like a Ponzi scheme, it can only maintain stability with ever larger numbers of new investors. If the demographics shift to a much older population due to a low birth rate, there won't be enough new investors to keep the scheme going. > 1. There are always more significantly more people between the ages of 20 and 65 than there are over 65 - the ratio is currently about 5 to 1 in the US. We'd have to see a catastrophic level of depopulation for this to become untrue. Even if everybody stopped having kids tomorrow, it would take 20-30 years before the ratio became unreasonably unbalanced. This is exactly the scenario that's predicted to play out in South Korea, which currently has a birth rate of 0.81. https://thediplomat.com/2022/08/south-koreas-demographic-trends-continue-to-decline/ https://thediplomat.com/2022/08/south-koreas-demographic-tre... "Workers between ages of 25-49, those who are in their prime working years, however, are expected to decline from 36.8 percent of the population to 23.1 percent by 2050." "Based on current trends, Statistics Korea estimates that senior citizens will account for 30 percent of the population in 2036 and 40 percent by 2051." The US isn't nearly as bad in terms of birth rates, but the decline in birth rates is a global trend that shows no signs of stopping. > 2. Social Security is in trouble because the government sees/has seen it as their private slush fund to spend on other things, not because it's inherently unsustainable. Social security IS inherently unstable, in that it will cease to be funded if there aren't enough young people.