But the three most conservative members of the court — Justices Clarence Thomas, Samuel A. Alito Jr. and Neil M. Gorsuch — issued a lengthy dissent, saying the majority had gone badly astray.

“Where many other states have adopted religious exemptions, Maine has charted a different course,” Justice Gorsuch wrote for the dissenting justices. “There, health care workers who have served on the front line of a pandemic for the last 18 months are now being fired and their practices shuttered. All for adhering to their constitutionally protected religious beliefs. Their plight is worthy of our attention.”

Maine has required health care workers to be vaccinated against various contagious diseases since 1989, and eliminated exemptions on religious or philosophical grounds under a state law enacted in 2019, before the coronavirus pandemic began. The state does exempt workers for whom the given vaccine would be “medically inadvisable” in the judgment of a health care professional.