Viewed from the vantage of a veteran litigator in the war against abortion, Utah's new law banning most abortions is no guaranteed "slam-dunk loser" in the U.S. Supreme Court.

Indeed, Richard Wilkins, a former assistant U.S. solicitor general who honed the nation's toughest anti-abortion legislation, gives the bill that hurtled through the statehouse this past week at least a 50-50 chance.But like legal authorities on both sides of the issue, Wilkins is mindful of the role to be played by the Supreme Court's two wild cards - justices Sandra Day O'Connor and David Souter.

"What we don't know is what Justice O'Connor and Justice Souter will do," said Wilkins, now a Brigham Young University constitutional law professor. "If either one of them votes with the majority, that's where the court will go."

The bill signed into law Friday by Republican Gov. Norm Bangerter aims at the heart of the court's 1973 Roe vs. Wade decision, which held that states cannot interfere with a woman's right to choose an abortion in the first trimester of pregnancy.

The legislation permits abortion to save the life of the mother, or to prevent grave damage to her health or the birth of a fetus with profound defects. Victims of rape or incest would have five months to abort if the crime were reported to police.

The bill's supporters hope it will convince the court to overturn Roe by sustaining the state's compelling interest in preserving unborn life without imposing "undue burden" on women who, for medical reasons, must have abortions.

Failing that, they hope it will strengthen states' regulatory power over abortion as in less stringent legislation enacted in Ohio, Missouri and Minnesota.

The law will not take effect until mid-May, but supporters expect it will be blocked in court well before then. Even Democratic Attorney General Paul Van Dam has said it may be unconstitutional.

Nevertheless, Wilkins told Republican lawmakers, "It's not a hoax, it's not a slam-dunk loser, it's not dead on arrival in the Supreme Court."

James Bopp Jr., general counsel for the National Right to Life Committee, is more optimistic, counting two-thirds of the court on his side.

"Based on what I know of the views of the justices on the court, I think we have six votes to uphold any abortion restriction or prohibition, up to and including one that would allow abortion only to save the life of the mother," he said.

Not so, says Rachael Pine, an attorney with the ACLU's Reproductive Rights Project that will marshal the legal battle against the Utah law. In her view, O'Connor and Souter are pivotal but unpredictable.

"O'Connor does not appear to be prepared to flatly overturn Roe. Now we need Souter and O'Connor," she said. "There are reasons for optimism that he might agree with (O'Conner's) position, but there's no way to know that whatsoever. It's an open field."

In fact, Wilkins said, the "undue burden" perspective O'Connor has adopted arose from a friend-of-the-court brief he wrote in a 1982 Ohio case, when the Reagan administration made its first effort to urge the court to retreat from Roe.

Souter, meantime, has steadfastly refused to tip his hand on abortion.

Wilkins sees the newest justice as "precedent-bound" and believes if Souter had been on the bench in 1973, he probably wouldn't have voted with the majority to legalize abortion.

Now that Roe is the precedent, Souter might be reluctant to throw it out, he said.

Bopp is more sure of O'Connor and Souter, saying the former has made it clear she believes there is a "compelling interest in the life of the unborn. That's sufficient to trump the right to abortion."

He believes Souter would find the Constitution does not ensure a fundamental right to abortion.

In any event, said the ACLU's Pine, the Utah case will take years to wind through the system. Pennsylvania's regulatory statute and Guam's ban on most abortions are pending in appellate courts and likely will precede Utah in the Supreme Court.

Meantime, restrictive bills have been introduced in Wyoming, South Dakota and Missouri, according to the National Abortion Rights Action League.

And Pine anticipates still more efforts by the states to chip away at Roe.

"The entire scenario is disheartening for those of us who feel that as a matter of principal, this issue should not be up for legislative vote at all," she said.