The Supreme Court has just struck a blow for male equality in the Social Security system, and an expensive blow it was. In one key area, men applying for benefits will now be treated the same as women - a change that affects the incomes of half a million men this year. The price to taxpayers in the first year has been figured at $500 million. Sooner or later, taxes will have to rise to cover that cost.

The wife of a man in Social Security-covered employment has always been eligible for a spouse's benefit at retirement. At age 65, that benefit amounts to 50 per cent of her husband's payment.

By contrast, the husband of a woman who worked in Social Security-covered employment could not get a spouse's benefit at retirement, unless he could prove that he had been financially dependent on his wife. "Dependence" means that she paid more than half of his support.

The same inequality divided widow's and widower's benefits. If a man died, his wife was automatically entitled to whatever payments were accorded a widow of her age. For example, if she started retirement checks at age 65, she'd get exactly what her husband would have received. But if a woman died, her husband had to prove dependence before he could get a widower's payment.

All that has changed. A husband of widower no longer has to prove dependence in order to collect on his wife's account.

The majority of men won't be affected by this, because their own Social Security benefit is larger than what they'd get as spouses. But three particular groups of men are now eligible for higher payments:

Men who made Social Security contributions only for a short time, or whose wages were low, and were married to women who contributed more to Social Security. Your benefit as a spouse may well be better than your personal benefit. Social Security estimates that there are 273,000 men in this position.

Men not eligible for any tax-financed pension, perhaps because they worked for a nonprofit organization that never joined Social Security. If their wives were covered, they can now add a spouse's benefit to whatever pension they get from private sources. This category includes some 34,000 men.

Men who don't get Social Security because they're getting Railroad Retirement or have government pensions - from the military federal civil serviceor state and local government. If their wives were in Social Security employment, they'll now get a spouse's benefit in addition to their government pensions, which are often substantial. This affects 213,000 men.

the effect of this ruling is to put these people in a more favored position service, for example , there could be three pensions in the family - his own government pension, his wife's Social Security benefit, and his Social Security benefit as a spouse. The rest of us get a spouse's benefit or our own benefit, but not both.