As an appeals court judge, Justice Kavanaugh dissented from a decision allowing an undocumented teenager in federal custody to obtain an abortion, writing that the majority’s reasoning was “based on a constitutional principle as novel as it is wrong: a new right for unlawful immigrant minors in U.S. government detention to obtain immediate abortion on demand.”

Ms. McGill Johnson of Planned Parenthood said Justice Kavanaugh appeared to hold the crucial vote in the new case.

“Three years ago,” she said, “the Supreme Court decided that laws like this one in Louisiana had no purpose other than to make abortion more difficult to access. There’s only one reason the court would not strike down the Louisiana law and that is because Justice Kennedy, who voted to protect abortion access just three years ago, has been replaced with Justice Kavanaugh.”

On Friday, the Supreme Court also agreed to decide a threshold issue pressed by Louisiana in a separate petition arising from the same case, Gee v. June Medical Services, No. 18-1460. The state argued that the abortion providers who filed the lawsuit lacked legal standing to challenge health and safety regulations on behalf of their patients.

If the court accepts that argument, it could avoid deciding whether the Louisiana law is constitutional.

But other abortion cases are likely to follow the one from Louisiana, whatever its outcome, because several state legislatures have enacted laws that seem calculated to try to force the Supreme Court to consider overruling Roe v. Wade, the 1973 decision that established a constitutional right to abortion. Mr. Trump has vowed to appoint justices who will vote to the overrule the decision.



The Louisiana law was struck down in 2017 by Judge John W. deGravelles of the Federal District Court in Baton Rouge, who said that doctors willing to perform abortions were often unable to obtain admitting privileges for reasons unrelated to their competence and that the law created an undue burden on women’s constitutional right to abortion.