>>150
It wasn't a scam. It worked quite well, providing funds for the government (it still does), and later providing money to people when they retire. It didn't matter what the government did with the money so long as what went in later came back out.
There's just one big problem:
the current system assumes that there are more younger people. Either the population keeps on expanding, or there is a high mortality rate. Since nowadays neither of these is the case in most Western societies, this assumption is false. Zero or lower population growth will put a nail in the coffin of social security.
I usually favour social policies, but you can't argue with math. The money will either need to come from elsewhere (cuts to other services, higher taxes, etc), or SS will need to go.