I suspect those who save wisely and privately saved for their retirement will see their nest eggs raided by the state if the public social security system collapses.
One of the reasons contributions made in to pensions in the UK are 100% tax free is because nobody trusts a future government not to double dip.
That's my fear as well. The last wall to topple is a straight tax on capital. Sure, they'll sell it as a tax on the uber rich just like they did with the income tax, but that threshold will drop drop drop until the middle class is paying out on both ends: tax on earned income + tax on everything you have. Every year.
As a US-er, everyone I've talked to regards me as overly cynical, but I think about Roth IRAs and to some extent all tax-advantaged retirement accounts the same way; that money is a fat target once it becomes politically expedient.
One of the reasons contributions made in to pensions in the UK are 100% tax free is because nobody trusts a future government not to double dip.