Slim majority

Americans Show Clear Concerns on Bush Agenda by Adam Nagourney and Janet Elder

On Social Security, 45 percent said a proposal to permit people to invest their Social Security withholding money in private accounts was a bad idea; 49 percent said it was a good idea.

The article links to the questionnaire which also asks this:

If people who chose to invest their Social Security taxes in the stock market lost their money, should it be the government's responsibility to make up the losses, or should this not be the government's responsibility?

80% have consistently stated that they don't believe it's the government's responsibility.