I think that Bush is on the right track on the Privitation of Social Security. Allowing the citizens the choice in what investments is right for them and allowing the freedom in taking a responsibility in the future of their payments will both stimulate the economy and allow a greater rate of return. One factor facing today's social security is that it's based upon the Index of The Treasury and that the pay out of it is secure it falls below the rate of inflation. This creates a situation where it will lose money over time.
By allowing the investment into the market will create the situation where your investment will yield a much greater rate of return then can ever be hoped to match by merely indexing it with the treasury. For instance creation of an index fund that mirrors the market. With an 8-10% rate of return we're talking about the doubling of the money in 8-10 years with compounding returns. By simply using the market forces Social Security will be saved.