The U.S. Supreme Court could decide this morning if Arizona is going to get a chance to enforce its ban on abortions at 20 weeks of pregnancy.

The justices scheduled a closed-door discussion last Friday of the state’s request that they review and overturn an appellate court ruling that found the ban is unconstitutional. Maricopa County Attorney Bill Montgomery, who has taken the lead on the case, contends legislators were within their rights to approve the 2012 law.

A decision by the high court to consider the state’s position would be just that, with no guarantee it will overturn the lower court ruling.

But it would mean that at least four of the nine justices want to take a closer look.

Hanging in the balance could be more than just the Arizona law. Several other states have

adopted similar statutes.

More significantly, the justices could use this case to revisit the historic 1973 precedent set in Roe v. Wade, which first spelled out a right to terminate a pregnancy.

The Arizona law

makes it a crime for a doctor to perform an abortion on a woman who is beyond the 19th week of pregnancy except when necessary to prevent a woman’s death or “substantial and irreversible impairment of a major bodily function.’’

Last year the 9th U.S. Circuit Court of Appeals said the law is unenforceable. The judges said Supreme Court precedents have made it clear women have an absolute right to terminate a pregnancy at any time prior to viability, something that does not occur until around the 23 or 24th week.

Montgomery, however, contends Arizona lawmakers have a legitimate interest in stepping in.

He cited some experts who say that a fetus can feel pain at 20 weeks. Montgomery also said the procedure has an increased risk to the mother after that point.

Appellate Judge Marsh Berzon, writing for the 9th Circuit, said all that is legally irrelevant.

“A woman has a constitutional right to choose to terminate her pregnancy before the fetus is viable,” she wrote. “A prohibition on the exercise of that right is per se unconstitutional.”

In a concurring opinion, Judge Andrew Kleinfeld dismissed the measure’s stated interest in protecting a woman’s health as a reason to keep her from getting an abortion at or after 20 weeks.

“People are free to do many things to their health, such as surgery to improve their quality of life but unnecessary to preserve life,” Kleinfeld wrote. “There appears to be no authority for making an exception to this general liberty regarding one’s own health for abortion.’’