This case was a challenge to the constitutionality of a Maine program that prohibits tuition for some students to attend private religious schools when their own school district does not operate a public secondary school.
The court 6-3, led by Roberts, holds that the Maine program violates the free exercise clause.
Because the benefits hinge on whether a school is religious, the Chief writes, the Maine program "effectively penalizes the free exercise" of religion.
Maine provides assistance for tuition for parents who need to send their children to private schools because of no public school available. But they won’t allow the tuition to be used for religious schools.
http://www.supremecourt.gov/opinions/21pdf/20-1088_dbfi.pdf