Congress' leading "pro-life" advocates, concluding they lack the votes to pass a constitutional amendment pohibiting abortion, have launched an effort to achieve the same end through the less burdensome procedure of passing a law. t

Sen. Jesse Helms (R-N.C.) and Reps. Henry J. Hyde (R-Ill.) and Roman L. Mazzoli (D-Ky.) have introduced legislation that would establish this statutory definition of the term "life:"

"Human life shall be deemed to exist from conception."

The sponsors argue that, if their bill passes, the 1973 Supreme Court decision voiding some state laws against abortion would be effectively nullified.

That decision was grounded on the Constitution. The court majority held that a woman's implicit right to privacy limits a state's right to govern abortion. Normally, it takes a constitutional amendment to undo a ruling based on constitutional law. But abortion opponents -- even with their gains in the last election -- apparently cannot garner the two-thirds majority in Congress that is required just to propose an amendment to the states for ratification. So they have been looking for legislative means to get around the court's holding. A majority vote in each house of Congress is needed to pass a law.

The proposed legislation, which antiabortion activists call the "Human Life Bill," aims to fill a gap in the law left by the 1973 court decision. The justices then said the law has not treated the unborn as "persons;" thus the woman's privacy interest had been the paramount concern. They based this conclusion on inferences from statutes and earlier court decisions and declined to answer what they called "the difficult question of when life begins."

The sponsors of the new bill want to legislate an answer. They say a statutory definition declaring that life begins at conception would mean an unborn fetus is, by law, a "person." Abortion would then legally constitute "the taking of a human life," according to Helms, and would no longer have constitutional protection.

Supporters of the proposed law acknowledge that Congress cannot normally resolve constitutional questions through legislation. But they point to the last sentence of the 14th Amendment, which says "Congress shall have power to enforce, by appropriate legislation, the provisions of this article." The sponsors argue that the authority to "enforce" the amendment includes the power to define its terms.

Like all other political initiatives in this field, the "human life bill" is surrounded with controversy. "It's a back-door attempt to amend the Constitution," says Suellen Lowry of the National Abortion Rights Action League. "They are trying to deny women a necessary medical service," she says. "They're trying it this way because they know they couldn't get the states to ratify it."

Supporters of legal abortion echo that point. Norman Dorsen, a New York University law professor who was one of the lawyers on the winning side in the 1973 decision, says there are "grave constitutional doubts" about "an effort to change the meaning of the Constitution by legislation."

Nonetheless, Dorsen says the legality of such a bill in the abortion field is "not a simple question" because of the reasoning the justices employed in the 1973 case. And Laruence Tribe of Harvard Law School suggests in his text "American Constitutional Law" that such a statute could be grounds for a court ruling that the fetus' right to life overrides the woman's right to an abortion.

". . . Nothing in the Supreme Court's [1973] opinion," Tribe says in a long discussion of arguments for and against the decision permitting abortion, "provides a satisfactory explanation of why the fetal interest should not be deemed overriding [in early pregnancy], particularly when a legislative majority chooses to regard the fetus as a human being from the moment of conception. . . ."

Whether there will ever be such a law for courts to consider, though, is still unclear. Neither House nor Senate subcommittee chairmen have immediate plans for hearings -- the first step toward passage -- and the appropriate subcommittee in the House, the civil rights subcommittee of the Judiciary Committee, has a majority that would seem unlikely to report the bill favorably.

The legislation's future probably lies in the Senate, where Orrin G. Hatch (R-Utah) is planning hearings on the general question of abortion sometime this year before his subcommittee on the Constitution.