Social Security isn’t the only cause of America’s fiscal problems, but it is Exhibit A in why it is so hard to fix them. No serious solution to our debt can ignore a program that will tax and spend about 4.8% of GDP this year and account for about 20% of all federal spending-and that within a few decades will count almost a third of the population as beneficiaries. But whenever I write about Social Security here at CBS MoneyWatch, I’m always struck by how much disagreement there is about how the system really works.

A handful of misconceptions tend to crop up repeatedly-often having to do with that fiscal fun-house mirror, the Social Security trust fund. And despite the efforts of writers like Allan Sloan and experts like the Urban Institute’s Eugene Steuerle, the myths won’t die. This column won’t kill them either, but that doesn’t mean we shouldn’t take a whack. Here goes:

Myth: Social Security didn’t create the deficit and shouldn’t be cut to fix it

This is a much loved progressive slogan. “Blaming Social Security for the deficit is like blaming Iraq for 9/11,” writes Dave Johnson of OurFuture.org in one of the cleverer examples of the genre.

Technically, the first part of the myth is true-or rather, used to be true. From 1983 until last year, Social Security revenues actually lowered the Treasury’s need to borrow in the public markets, as excess payroll taxes collected under Social Security’s flag helped fund other government programs.

The surplus years are over, however. The Social Security trustees’ report estimates that last year payroll taxes fell short of the sums paid out to beneficiaries. Small surpluses will return for a few years; then the red ink will return for good in 2015. To make up the annual shortfall, Social Security will have to draw on revenues from the general budget. In other words, from here on out, year after year, Social Security only makes the deficit larger.

Myth: Social Security benefits are earned; reducing them amounts to confiscation

It’s not hard to see why this illusion exists, since Social Security’s own website refers to “earned credits” and sometimes refers to payroll taxes as contributions. But despite Social Security’s fetish for language that echoes private pensions, no one ever vests in Social Security. You don’t own your benefits until you cash the check.

It’s more accurate to say your benefits are an entitlement granted by act of Congress and subject to change at any time by another act of Congress. As long as voters consider benefits inviolate, they will be. When voters decide fiscal responsibility is more important, then Social Security benefits- “earned” or not-will be up for review.

Myth: Social Security is funded until 2037

The Social Security trust fund–the ledger on which Uncle Sam records the surplus taxes that the program has accumulated over the years–is large enough that the program need not ask for extra money to pay benefits until 2037, the year that the trust fund “runs dry” if nothing changes. But that’s not the same as being funded-at least not in a way that has any economic meaning.

As you may know, the trust fund is, for accounting purposes, assumed to be invested in IOUs from the U.S. Treasury. When Social Security needs money beyond what it expects to collect in payroll taxes, it can redeem some of these IOUs. But it’s not as if the trust fund is a giant 401(k). It’s more like access to a rich but cash-strapped daddy’s credit card.

What that means is that Social Security can get what it needs from Treasury without having to ask permission from Congress. But when it redeems one of these IOUs, the Treasury (just like Daddy) has to come up with the money the old-fashioned way, by raising taxes or, more likely, borrowing more.

Dolly Madison at Daily Kos seems to think that Social Security’s need for cash can be met from the interest credited to the trust fund-that is, with more IOUs. Allan Sloan disagrees:

You know, of course, why this wouldn’t work — at least, I hope you know. It’s because the U.S. government ultimately has to pay its bills with cash, not with its own IOUs. In the long run, you need cash — real money — not funny money.

“Fully funded” suggests that the money to maintain today’s benefits until 2035 is already locked up. It isn’t. Redeeming IOUs from the trust fund (and the income imputed to those IOUs) will only put another burden on taxpayers who are simultaneously paying for Medicare, interest on the debt, and all the other purposes of government. At some point, the total burden will be too much.

Myth: The trust fund is invested in Treasury bonds, the most secure investments in the world. To suggest that the trust fund wouldn’t pay is blatant fear mongering.

The trust fund’s IOUs are entered on the Treasuries books as non-trading “special issue” bonds, paying interest at a rate equal to an average of outstanding Treasuries. And yes, the Treasury will undoubtedly pay if Social Security asks.

But that’s not the issue. The issue is whether taxpayers think it’s so important to maintain Social Security benefits that they will gladly absorb the burden of paying off those bonds on the current schedule. Remember, Congress (that is, you know, taxpayers) can cut benefits-and thus postpone the need for Social Security to redeem any bonds–just by passing a law.

In other words, the myth misses the point. Whether Social Security continues to pay benefits at today’s rates isn’t a question of credit quality. It’s a question of politics and priorities.

Myth: Social Security is an easy fix

Any policy wonk worth his or her spreadsheet can quickly come up with ways to bring Social Security into long-term actuarial balance. You can conjure up solutions yourself using the Committee for a Responsible Federal Budget’s calculator. You’ll find it’s not that hard to wipe out the system’s long-term deficit.

The only problem is, most such solutions regard Social Security as a closed system. They assume that the trust fund is an ATM that gushes cash whenever the trustees demand, and that workers will never balk at stepping up to higher payroll taxes.

Which brings us to what may be the most destructive myth of all: The idea that Social Security is, fiscally speaking, an end in itself. In the real world that Social Security actually operates in, the government and its citizens all have other obligations. As Steuerle puts it:

Social Security as a budget issue revolves not simply around its internal accounting balances and trust funds, but rather how much of the economy it occupies and how much of future growth it absorbs.

The discussion we need to have, then, isn’t simply whether we can pull the levers to bring Social Security into balance. That is easy. Instead, we need to ask a larger, tougher question: In light of all we owe-to our creditors, our children and our future-how much do we want to spend supporting everyone who happens to live past 62? We want to spend something, to be sure, and maybe a lot. But myths and slogans shouldn’t persuade us that we can avoid the question. We can’t.

[A version of this post previously appeared on The Fiscal Times]

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