PayGo NoWork

Here is Brad DeLong's reason number 4 to favor private accounts for social security:

We need to raise our national savings rate. But if we just raise Social Security taxes, Congress will treat these taxes as general revenue and spend them. Only by funneling Social Security contributions into some vehicle that Congressional representatives cannot interpret as a resource available to fund current spending can we raise the national savings rate. And private accounts are the best vehicle we can find to (a) accumulate contributions without (b) allowing Congressional representatives to seize them as resources available to fund current federal spending.

That reason receives new support from Nataraj and Shoven who present evidence that:

...the trust fund build-up may not help future generations due to the adoption of the Unified Budget in 1970. The Unified Budget includes trust fund receipts as income and trust fund payments as expenditures. The empirical evidence suggests that attempts to balance the Unified Budget while the trust funds were generating surpluses has led to increased government spending and personal and corporation income tax cuts within the rest of the federal government. There is no evidence of increased government saving as a result of the trust fund accumulations.