The Florida Supreme Court’s conservative justices repeatedly questioned on Friday whether the state’s privacy rights extend to abortion as they considered whether to uphold a ban on the procedure after 15 weeks of pregnancy — a decision that could overturn decades of legal precedent and trigger a far more restrictive ban.

Such a decision would cement Florida’s transformation from a haven for women seeking abortions in the American South to a state with some of the most severe restrictions on the procedure, which were enshrined into law by Republicans who have also shifted the ideological balance of the high court from liberal to conservative.

Should the court affirm the 15-week ban, as expected, that would trigger the more recently approved six-week ban to take effect 30 days later, a dramatic policy shift for a state that up until last year allowed abortions up to 24 weeks of pregnancy. Few women know they are pregnant by six weeks, and abortion rights backers say such an early ban amounts to near total prohibition. The justices did not indicate when they would rule.

During a closely watched oral argument in Tallahassee on Friday, a lawyer for Planned Parenthood, the American Civil Liberties Union of Florida and several abortion providers argued that the court should not narrow the scope of the privacy rights that Floridians have relied on for 40 years. The state’s solicitor general countered that the court erred in extending privacy rights to abortion, as it first did in 1989.

Several justices appeared sympathetic to the state, questioning whether Florida voters intended for the explicit right to privacy written into the State Constitution in 1980 to include abortion. The constitutional provision states: “Every natural person has the right to be let alone and free from governmental intrusion into the person’s private life.”

“If the original public meaning of that text included abortion, you would expect to see positions from Planned Parenthood and National Right to Life debating each other in 1980,” Justice John D. Couriel told the lawyer for the plaintiffs. “And yet we don’t really see that.”

Whitney Leigh White, the plaintiffs’ lawyer, countered that lawmakers and voters understood in 1980 that the privacy clause “unambiguously” extended to decisions that people could make about their own bodies, which she called “decisional privacy.”

“Legislators were fully informed and fully on notice that the privacy laws were broad,” she said, adding that voters subsequently rejected an amendment in 2012 that would have exempted abortion from constitutional privacy protections.

But Henry Whitaker, the solicitor general, said that lawmakers and voters in 1980 were trying to protect people from government intrusion into their personal data, which he called “informational privacy.”

“As a matter of common sense, intrusion — not interference, intrusion — into a person’s private life are words that are historically associated with informational privacy,” he said.

The privacy argument was also used in the landmark Roe v. Wade decision that enshrined the federal right to abortion in 1973. U.S. Supreme Court justices rejected that argument in their decision to overturn Roe last summer.

Florida’s abortion picture has been confusing for more than a year. The 15-week ban, enacted in 2022 shortly before Roe was overturned, was allowed to take effect while the case challenging its constitutionality wound its way through the courts. A trial judge ruled that it violated the state’s privacy protections.

Then, in April of this year, Gov. Ron DeSantis, a Republican who is now running for president, and the G.O.P.-held State Legislature enacted the six-week ban, with the 30-day trigger clause should the 15-week ban be affirmed in court.

A coalition of groups that includes Planned Parenthood and the A.C.L.U. is seeking to put a question on the Florida ballot next year asking voters to amend the State Constitution to effectively include the right to abortion up to around 24 weeks.

Mr. DeSantis has campaigned on reshaping the court by appointing five of its seven justices. The other two justices were also appointed by a then-Republican governor, Charlie Crist. One of them, Justice Charles T. Canady, sponsored anti-abortion legislation as a member of Congress and is married to State Representative Jennifer Canady of Lakeland, who co-sponsored the six-week abortion ban this year in the State House.

One of Mr. DeSantis’s appointees, Justice Jamie R. Grosshans, did pro bono legal work for pregnancy centers that discourage women from having abortions, The Miami Herald reported in 2020. The Washington Post reported earlier this year that another DeSantis appointee, Chief Justice Carlos G. Muñiz, once affirmed Florida’s constitutional abortion protections in a legal article.

On Friday, Chief Justice Muñiz and Justice Grosshans acknowledged that a ruling in the state’s favor would affect myriad other precedents unrelated to abortion that have relied on a broad interpretation of privacy rights over the past 30 years.

But Chief Justice Muñiz also said that society has debated abortion for decades amid new medical advancements. If lawmakers should now decide that abortion should be restricted, he continued, then it may not be the court’s role to say that is inappropriate.

“This is a 50-year reflection by our society, by our state,” he told Ms. White. “The people’s elected representatives believe there is a compelling interest in protecting human life. Why should we as a court not defer to that?”