[madprof98]

Justice Thomas went to Catholic school as a child and even studied in a Catholic seminary for a while. He left the Church later on and attended an Episcopal Church, but he is now a practicing Roman Catholic.

Here's how Wikipedia explains his situation:

Since joining the Supreme Court, Thomas requested an annulment of his first marriage from the Roman Catholic Church, which was granted by the Tribunal of the Roman Catholic Diocese of Arlington. He was reconciled to the Church in the mid-1990s and remains a practicing Roman Catholic.

[xzins]

See #39

That explains “calvinist” catholic.