The president of Princeton University sent a letter Friday admonishing members of the Senate Judiciary Committee to avoid imposing a “religious test” on judicial appointees.

In the letter, Christopher Eisgruber expressed deep concern over several questions posed to Professor Amy Barrett of the University of Notre Dame, a nominee to the 7th Circuit Court of Appeals, during her confirmation hearings, urging the Committee to "refrain from interrogating nominees about the religious or spiritual foundations of their jurisprudential views."

"Refrain from interrogating nominees about the religious...foundations of their jurisprudential views."

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Eisgruber referenced the prohibition on religious tests for public office found in Article VI of the U.S. Constitution, as well the 1961 Supreme Court case Torcaso v. Watkins, in which the Court unanimously ruled that the same proscription against religious tests applies to the states as well as the federal government by incorporation via the First and Fourteenth Amendments.

The letter was addressed to the Republican chairman of the Committee, Sen. Chuck Grassley (Iowa), and the ranking Democrat, Sen. Dianne Feinstein (Calif.). The other members of the Committee were copied.

During Barrett's hearings, Feinstein commented on her Catholicism, saying, "when you read your speeches, the conclusion one draws, is that the dogma lives loudly within you. And that's of concern. When you come to big issues, that large numbers of people have fought for years in this country."

Feinstein's comment came despite Barrett stating earlier in the hearing that "it is never appropriate for a judge to apply their personal convictions whether it derives from faith or personal conviction."

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Eisgruber is a constitutional scholar who earned his JD cum laude in 1988 from the University of Chicago Law School, where he was editor-in-chief of the University of Chicago Law Review. He was previously a Rhodes Scholar at the University of Oxford, where he earned his master of letters degree in 1987.

In a tweet unrelated to Eisgruber’s letter, conservative Princeton professor Robert P. George condemned Feinstein’s “disgusting” attack on Barrett’s faith, labelling it “liberal bigotry” and calling for the Democratic senator’s resignation.

Follow the author of this article on Twitter: @mpenza19