Just going off the LP website:

"Libertarians believe you should be able to opt out of Social Security and invest your money in your own personal retirement account. An account that you own and control - one that politicians can't get their hands on."

Seeing as how it will take 40+ years to cycle through all the people who have "paid into the system", are you suggesting Johnson & company would wait that long before privatizing it? Hardly. There's a reason why privitization has gone nowhere, and it's because it's a big first step towards gutting SS as well as being a big payoff to the Wallstreet casino( where gobs of former SS contributions would wind up). SS, one of the better run govt. programs, needs tweeking not gutting. This position alone is why I could never vote Libertarian.