There's nothing wrong with using T-Bills, the problem is that the T-Bills are not owned by the worker for 12.5% of his lifetime earnings. And, if any money is

There's nothing wrong with using T-Bills, the problem is that the T-Bills are not owned by the worker for 12.5% of his lifetime earnings. And, if any money is saved it's just a temporary measure b/c the program is designed as a pay-as-you-go program, where the taxes paid by current workers are sent to current retirees. So it's really not investment that is going on, merely a very temporary surplus. I don't approve of raising the income cap because that fails to address the regressive nature of the tax. It also fails to address the larger issue, which is the vulnerability of the program to demographic shifts and congress's whims, including the oft-used whim of spending the current surplus on other things to avoid having to raise taxes now for current spending. I think the best solution would be to give workers below a certain age the option of opting out of the pay-go program and instead choosing an investment based program curated by the government but with an ownership component. The missing revenue should just be paid for via our progressive income tax regime.