I must disagree. Judicial philosophy is the most important factor. I am sure even you would say that Justice Clarence Thomas, a Catholic, is about a hundred times better than Harriet Miers, whose main qualification was being a born-again Christian, would ever be. And, as this very case shows, a Mainline Protestant - Justice Gorsuch - may understand the Constitution too.
“Judicial philosophy is the most important factor.”
Correct. And what determines Judicial philosophy?
Background, education and religious values. The understanding that a Civil Right cannot be a Moral Wrong.