ALL ALONG, it's been one of the tough questions in the whole abortion controversy, and one brought on by ingenious and tenacious anti-abortion forces in Congress. The Supreme Court has ruled that a woman has the right to have an abortion, but the question remains whether an indigent woman who is medically needy has the right to have the taxpayers pay for it.

I know how the antiabortionists feel. It's a little like some of us felt years ago when we were paying taxes and finding that they weren't going for the good things like public education and transportation and clean air. They were going, instead, to the Vietnam war. The antiabortionists haven't been the first group to be profoundly morally offended at the way Congress spends money; they've just been a little more effective than others in thwarting it.

The antiabortionists have been able to hitch amendments to appropriations bills since 1976, forbidding the use of federal Medicaid funds for abortions, except when the life of the mother is in danger or when the pregnancy relsults from rape or incest. The net effect of the legislation, known as the Hyde Amendment, has been that for the past three years most poor women have had trouble getting legal abortions because they can't afford them and the federal government won't pay for them.

The key words in the latest abortion dispuute are "medically needy." In 1977, the Supreme Court ruled that the states have the right to restrict public financing of "nontherapeutic" abortions. Monday morning, the court heard arguments on the other side of that question: what about the indigent woman whose life is not immediately, clearly endangered by a pregnancy, but whose mental and physical health is endangered? Medicaid would pay for almost all her other medical needs. Should federal Medicaid funds pay for her abortion?

The number of pregnancies in which a woman's health is endangered is unknown, according to a brief filed on behalf of a group of poor women, but the issue here is not number, it is individuals. This Supreme Court case has to do with the mother of three who got phlebitis and whose fourth pregnancy increase her risk of getting blood clots in the lung. It has to do with a 16-year-old mother of two with rheumatic heart disease, with an 18-year-old victim of rheumatoid arthritis who had a previous child by cesarean section after being crippled most of the pregnancy. It has to do with the 14-year-old diabetic, with the 15-year-old schizophrenic, with the 33-year-old mother of three who got pregnant on a weekend furlough from a state mental hospital.

Many of the women plaintiffs in this case were taking medication that they could not continue taking while they were pregnant because the medicine might harm the fetus. Pregnant women with cancer have had to stop radiation and chemotherapy treatments because of danger to the fetus.

This Supreme Court case, known as Cora McRae, et al, also has to do with healthy poor women who know they are carrying abnormal fetuses. It has to do with people such as Donna Edwards, the wife of a Navy man, who found out she was carrying an anencephalic child, a child with no brain, skull or spine, a child born to die. Donna Edwards was forced to carry that baby to term and give birth to her, because of a Hyde Amendment to the defense appropriations bill. Mrs. Edwards' condition was positively diagnosed after the pregnancy had advanced to a point that paying privately for an abortion was beyond the couple's means.

Monday morning, Rhonda Copelon of the Center for Constitutional Rights in New York City, argued that denying poor women Medicaid funds for medically needed abortions violated several of their constitutional rights, including the rights to due process and equal protection. She argued that the Hyde Amendment is grounded in the fundamentally religious doctrine that life begins at conception -- a belief held by the Roman Catholic Church, Orthodox Jews and a number of fundamentalist regions -- and that the law is therefore unconstitutionally biased in favor of one religious belief.

And she tried to talk about people. She tried to tell the justices about doctors having to wait until a woman was going to die before performing an abortion, about women getting pregnant while using an intrauterine device and running a 50 times greater risk of developing an overwhelming and sometimes fatal infection in the second trimester of the pregnancy if the IUD can't be removed.

She argued that the Hyde Amendment, far from embodying the legitimate concerns of a government to encourage normal childbirth, encourages abnormal childbirth. The Hyde Admendment, she said, changes the balance of concern to an absolute preference for fetal life over the health and life of the mother when the Supreme Court has already decided that the fetus is not a person for purposes of the Constitution.

The government's position is that Congress has the right to decide how it is going to spend the taxpayers' money. Solicitor General Wade McCree maintained that the Hyde Amendment doesn't prevent women from getting abortions, it just denies them federal funds. He also acknowledged that some women will suffer medical harm because of this, but said Congress can't solve all social ills. He did concede, however, that Congress was taking the more expensive way out of this social ill since it costs considerably more to provide a poor woman with prenatal, obstetrical and postpartum care than it does to abort the fetus.

Copelon, fielding the usual interruptions from the justices, tried to argue the inhumanity of the Hyde Amendment and she tried to argue the illegality of it. She said it wasn't fair and it wasn't rational, that the "preference for fetal life at the expense of maternal life is irrational."

That got to Justice William Rehnquist, who has consistently voted to limit the availability of abortions. He finally exploded: "By irrational, do you mean Congress acted off the wall?"

Copelon said no, that what she meant was that Congress had passed a law that doesn't make sense "in the scheme of our Constitution." That's the way lawyers talk to the court. But if you read the brief the lawyers wrote to the court and read about the women who were denied abortions because of the Hyde Amendment, you come away with the feeling that Rehnquist, unintentionally, said it best of all.