(MONEY Magazine) – If you took your spouse "for richer or poorer," you now have a chance to prove it. The new 1997 tax law gives bigger tax breaks to many couples who choose not to wed. That means that the so-called marriage penalty--a tax code quirk that forces many working couples to pay more tax than if they had stayed single--just got worse. For example, married couples whose combined income tops $150,000 won't be allowed to fully fund the new $2,000-a-year Roth Individual Retirement Account. But singles will be able to contribute the maximum to a Roth IRA if their incomes are as high as $95,000.

Similarly, the new child credit, which can shave as much as $400 a child off your taxes next year ($500 a child thereafter), phases out completely for a couple who have one child and will make more than $118,000 in 1998 ($120,000 in 1999 and beyond). So if you and your spouse each make, say, $60,000, you wouldn't qualify for the credit. You would qualify if you were unhitched, however, since the credit doesn't phase out for, say, a divorced taxpayer with a child (who generally files as "head of household") until income tops $83,000 in 1998 ($85,000 in 1999 and thereafter).

Alas, despite recent political posturing to the contrary, Congress probably won't end the marriage penalty anytime soon, since doing so would be too costly to the Treasury. So if you're thinking about tying the knot in '98, keep in mind that you could benefit from some new tax breaks for an extra year by postponing your nuptials until the following January.

--K.S.