Can Liberals tell me why this is a bad idea?

Instead of putting Social Security deductions into the general fund where they are spent on anything and everything, ALL deducted money should go directly into individual accounts and used to buy government savings bonds. No risky stocks or mutual funds. No gold, No real estate. Money would only become available when the individual retires and if the person dies, the proceeds go to the heirs. Distributions come from redeeming bonds according to a schedule only when needed while those not redeemed continue to earn interest.