Conservative Supreme Court justices on Wednesday indicated support for upholding a restrictive Mississippi abortion law in a decision that threatens to erode, or even annul, the landmark 1973 Roe v. Wade ruling legalizing the procedure across the United States.

Jackson Women's Health Organization, the only abortion clinic in Mississippi since the only other one in the state closed in 2006, has challenged the conservative-backed legislation and has the support of US President Joe Biden.

Biden, a Democrat, reiterated that stance on Wednesday, as he told reporters: "I continue to support" Roe v. Wade.

Conservative majority among justices

The court heard arguments in which the justices are being asked to overrule the Roe v. Wade ruling which legalized abortion. The legalization of the procedure was challenged in 1992 and at that time the court sided with the Roe decision of 1973. As a result of those rulings, states can regulate — but not ban — abortion up until the point of viability, at around 24 weeks.

The court, which has a 6-3 conservative majority, heard arguments from both sides in Mississippi's attempts to revive its ban on abortion starting at 15 weeks, a Republican-backed law that was blocked by lower courts. During the exchanges, which lasted roughly two hours, the three liberal justices were vehement in their argument against abandoning longstanding legal precedents like Roe.

But Chief Justice John Roberts and Justice Samuel Alito were among those who questioned the viability line, with the latter, who was appointed after being nominated by President George W. Bush in 2005, arguing that "there are circumstances in which a decision must be overruled simply because it was egregiously wrong at the moment it was decided."

And fellow conservative Roberts asked: "Why is 15 weeks not enough time?"

Protests outside courthouse

Hundreds of protesters from both sides of the abortion debate rallied outside the court as proceedings got underway.

Anti-abortion protesters, many of whom were not wearing a mask, brandished placards outside the court reading "abortion is murder," while others held Christian crosses. 

Meanwhile, abortion-rights activists chanted: "What do we want? Abortion access. When do we want it? Now."

A ruling is expected by the middle of next year.

jsi/sms (AP, Reuters)