Lets say for example that the government starts hatching SS and Medicare in a big way. Since those funds were earmarked for retirement not general fund and since the fund was clearly mismanaged at times and people have been charged their whole life with specific expectation offered. It is in fact a retirement insurance that has become a rock solid expectation and took money that could of been invested elsewhere out of people's pockets at knifepoint.
Can they be sued by say AARP to hold up their end of the deal?