NEW YORK (CNN/Money) - My wife and I think 529 college-savings plans are great, but we're concerned about the sunset clause that will end their tax-free advantage on Dec. 31, 2010. Do you think this will really happen, or will the law be amended to make this benefit permanent?

-- Brett Boxell, Chatsworth, Calif.

Don't you just hate it when our esteemed legislators pass laws that make it impossible to do reasonable long-term financial planning?

I mean if it were just occasionally, maybe we could overlook it. But this kind of "the right hand giveth while the left hand prepareth to take away in the near future" lawmaking seems to be becoming de rigeur in our nation's capital.

Indeed, the relief we've seen in recent years in lower income tax rates, reduced levies on capital gains and dividends, higher 401(k) limits, estate tax rates and more are subject to being reversed because of these damned "sunset provisions" Congress has taken to writing into the laws. It's like taxpayers are being forced to ride in perverse version of the "Way-Back" machine that Sherman and Mr. Peabody used to travel back in time on the old Rocky and Bullwinkle show.

Sorry about the rant, but it's just so frustrating -- not just as someone trying to do planning myself, but also as a personal-finance journalist trying to impart worthwhile advice. Fact is, though, I don't have any better clue of what Congress is going to do on this issue than Congress does itself.

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Given the size of the budget deficits we've been racking up lately, I can see why Congress might be awfully tempted not to renew the 529 plan feature that allows qualified distributions -- generally, withdrawals for tuition, books, living expenses, etc. -- to escape federal taxes when that provision expires at the end of 2010.

After all, one way to close the budget gap is to raise revenue, and taxing withdrawals from 529 plans (which now hold upwards of $20 billion in assets) is one way to get some more money flowing into government coffers.

On the other hand, the very fact that these programs have been so popular with parents may make it difficult for Congress to rescind the tax-free status of qualified withdrawals.

After all, it could be seen as a sort of bait-and-switch. I'm sure we'd have lots of disgruntled parents, especially those who find that 529 withdraws not only have to cover rising college costs, but taxes as well. And disgruntled parents translates to disgruntled voters, which I would think is a situation lawmakers running for re-election would want to avoid.

Who knows, perhaps strong growth in the economy over the next six years combined with restraint over government spending will reduce the size of budget deficits and make it easier for Congress to extend 529s' favored tax status.

But if that doesn't happen, I think it will come down to which force is greater: the need for additional tax revenue or the fear of disenfranchising parents who are grappling with one of the major financial issues of today, paying for skyrocketing tuition.

My take is that it's going to be too difficult politically to let the 529 tax break simply sunset. So my guess is that the break will be extended.

If that doesn't happen, perhaps Congress would allow money invested before 2011 to be withdrawn tax-free but revoke the tax-free status for qualified withdrawals attributable to money invested after 2010. That, of course, would lead to a whole set of complicated rules to determine which pot of money a withdrawal comes from, which, of course, is just the kind of thing Congress loves. Absurd complexity.

In any case, if I felt that a 529 plan were a good way to save for my child's college education, I wouldn't let the possibility of the tax break fading into the sunset dissuade me from investing in such a plan.

After all, there are other advantages. Some states offer tax-deductions on contributions to the home state's 529 plan. And even if qualified 529 withdrawals do end up getting taxed, they're considered income of the beneficiary.

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For more on 529s, including a look at the specifics of your state's plan, click here. So unless your little scholar has an income as large as yours -- in which case, hey, the kid can pay for his or her own education -- then the tax bite is likely to be lower than what it would be had you invested the funds in your own non-529 account.

That said, I always think it's a good idea to hedge your bets. So at the very least you should consider rounding out your college fund with 529 alternatives such as Coverdell Educational Savings Accounts or even investing in tax-efficient mutual funds so that the bulk of your withdrawals would end up being taxed at low capital gains rates, assuming, that is, that Congress doesn't sunset those too.

Walter Updegrave is a senior editor at MONEY Magazine and is the author of "Investing for the Financially Challenged." He also answers viewers' questions on CNNfn's Money & Markets at 4:40 PM on Mondays.