It is more than a tad ironic that some members of Congress are pushing for a temporary "payroll tax holiday" at the same time the Presidential Social Security Commission is trying to find a way to pay for the trillions of dollars in unfunded benefits the nation's retirement system is facing.

Certainly, the tax holiday idea, whereby both employers and employees would be exempt from paying their share of the 12.4 percent payroll tax for a month, has many things going for it. It could boost holiday season spending by giving shoppers extra cash. It could leave businesses with more money on hand at a time when many of them are trying to avoid cutting costs by laying off workers. And it would provide a tax rebate for workers on the low end of the income spectrum who don't pay income taxes and therefore didn't qualify for the first round of tax rebates, but are hit by the hefty payroll tax nonetheless.

At the same time though, suspending payroll taxes, even for only a month, would drain the Social Security trust funds of roughly $40 billion dollars. That won't make a difference this year, or next, during each of which the program is expected to run surpluses of more than that amount. But it will affect the longer-term solvency of the already cash-strapped program. No one can argue that $40 billion isn't real money.

Proponents of the tax-holiday plan have suggested using general revenues from the rest of the budget to make up the difference to Social Security. This in itself would be no small change. One of the defining features of the program is that it is funded through the dedicated payroll tax. In the past when the program's revenues and expenditures have become misaligned, either taxes have been adjusted upwards or benefits reduced to keep the program in balance. A massive general revenues infusion would break a long-standing precedent. Certainly, such a decision should be based on the needs of the Social Security program rather than the desire to break the stalemate in Congress about how to craft a temporary stimulus plan.

What the tax holiday idea does demonstrate, is that the idea that the "lockbox" -- a budgetary gimmick championed by politicians on both sides of the aisle as recently as a few months ago -- amounts to saving Social Security, should be put to rest once and for all.

The amorphous lockbox was meant to be a mechanism whereby the past policy of using Social Security taxes to pay for other government spending would be ended, and the funds would be used only to reduce the government debt and thus saved for when they were needed. Even when the idea had a semblance of credibility, it would not have been sufficient to make the retirement program sound, (trillions of more dollars would still have been needed,) but had it been adhered to, it would at least have been a start.

But no one should be surprised that those surpluses sitting in Washington have proven to be too tempting to politicians. The Social Security surpluses were spent for sixteen of the past eighteen years; no budgetary gimmick is strong enough to change that when it means foregoing other tempting uses for the money with more immediate political payoffs. This year alone, both the President's tax cut and new spending priorities in Congress managed to pry open the rather flimsy lock. And with the immediate needs of responding the to terrorist attacks, saving Social Security's surpluses has been all but forgotten.

Whether the payroll tax holiday is enacted or not, there is more than enough evidence that lockboxing Social Security's surpluses is not an effective nor an enforceable means of reform. When the Social Security Commission's recommendations are made in just a few weeks, there are sure to be plenty of objections. Detractors of the private investments accounts the Commission favors, will inevitably be quick to shoot any and all of the proposals down.

(Conveniently, they will ignore the fact that had the surpluses been saved in private investments accounts, the question of whether the government should spend the funds on other programs would never have been broached.)

And while the issue of how best to reform Social Security deserves serious discussion, it is beholden on those who oppose the proposals put on the table by the Commission to provide credible alternatives.

It should by now be exceedingly clear, that the lockbox is not one of them.