School children utter the phrase “one nation under God” as part of the Pledge of Allegiance. The national motto, “In God We Trust,” appears on U.S. currency. Congress and many state legislatures start their sessions with prayers, and the U.S. Supreme Court opens oral arguments with the invocation “God save the United States and this honorable court.” Most presidential inaugural addresses refer to God, and most presidents have followed George Washington’s example in issuing Thanksgiving proclamations, many of which have referred to “Almighty God.”

Through these and many similar practices, the government invokes the concept of a deity. Opponents of these religious invocations say such proclamations promote religion and thus violate the First Amendment’s Establishment Clause, which prohibits all laws “respecting an establishment of religion.” Defenders of governmental religious invocations, by contrast, claim that such expressions do not explicitly promote religion; rather, defenders say, religious proclamations merely acknowledge the historical and cultural connections between the United States and belief in God.

In an influential 1962 lecture, Dean Eugene Rostow of Yale Law School argued that the government’s “conventional and uncontroversial” expressions of faith, which he called acts of “ceremonial deism,” do not violate the Establishment Clause. Although the Supreme Court did not explicitly use the phrase until 22 years later, the high court nevertheless employed the concept of ceremonial deism in the intervening years. For example, in Marsh v. Chambers (1983), the Supreme Court held that the widespread practice of opening a legislative session with a prayer does not violate the Establishment Clause. In its ruling, the court explained that legislative prayer has become “part of the fabric of our society” through its “unambiguous and unbroken history of more than 200 years.” This long history, the court reasoned, demonstrates that legislative prayer poses no real threat of establishing religion.

A Supreme Court justice first used the phrase “ceremonial deism” in an opinion in Lynch v. Donnelly (1984). By a vote of 5-4, the court in Lynch upheld the constitutionality of a city-sponsored Christmas display that featured a nativity scene as well as less-religious Christmas symbols such as reindeer and candy canes. In his dissenting opinion, Justice William Brennan wrote that while he thought this particular Christmas display was unconstitutional, less controversial expressions of religion might be permissible under the Establishment Clause. Citing Dean Rostow, Brennan argued that certain official references to a deity – such as the inclusion of God in the Pledge of Allegiance – might be constitutional “as a form [of] ‘ceremonial deism.’ ” According to Brennan, these expressions might not violate the Establishment Clause “because they have lost through rote repetition any significant religious content.”

After Brennan’s dissent in Lynch, the phrase “ceremonial deism” appeared frequently in judicial opinions. Five years after Lynch, the Supreme Court used the phrase in its opinion in County of Allegheny v. ACLU (1989), a case that upheld one government-sponsored religious display but invalidated another. Writing for the majority, Justice Harry Blackmun explained that the display of a Christmas tree and Hanukkah menorah outside the Allegheny City-County Building was constitutional because these objects, placed next to one another, represented the holiday season in general rather than a particular religion.

But in the same decision, the court struck down a display of a stand-alone nativity scene on a stairway landing inside the Allegheny County Courthouse. In explaining why this second display was unconstitutional, Blackmun stressed the importance of “function and history.” Blackmun argued that if the function of a religious expression is to solemnize an event, and if the expression has traditionally done so, then it is likely permissible under the U.S. Constitution. Because the nativity scene at issue in County of Allegheny was erected to celebrate the birth of Jesus, not the holiday season in general, and because the government had not historically displayed such nativity scenes, the court found the display unconstitutional.

Fifteen years after County of Allegheny, Justice Sandra Day O’Connor returned to the idea of ceremonial deism in her concurring opinion in Elk Grove Unified School District v. Newdow (2004). In this case, atheist Michael Newdow claimed that his daughter’s public school violated the Establishment Clause by including the phrase “under God” when school officials led recitations of the Pledge of Allegiance. The high court held that it did not have jurisdiction to rule on Newdow’s claim because he did not have legal custody of his minor daughter.

O’Connor did not join the majority opinion that found the court lacked jurisdiction; instead, she wrote that the court should have exercised its jurisdiction and upheld the pledge’s reference to God as a constitutionally permissible expression of ceremonial deism.

In reaching her conclusion, O’Connor proposed four questions for determining whether a government-sponsored message is a permissible act of ceremonial deism: (1) Is there a widespread practice of reciting the message? (2) Is reciting the message an expression of worship? (3) Does the message favor a particular religion? (4) Is the religious reference a minor part of the entire message?

Applying these four criteria to the Newdow case, O’Connor found the recitation of the Pledge of Allegiance in public schools to be a constitutionally acceptable act of ceremonial deism. She argued that the phrase “under God” in the pledge has been in widespread public use ever since Congress added these words to the pledge in 1954. Since then, O’Connor observed, many people throughout the nation, both in and out of school, have recited this phrase. O’Connor further asserted that the tone and content of the pledge suggest that reciting it serves as an act of patriotism, not one of worship. In addition, O’Connor noted, the pledge’s reference to God does not favor any faith in particular. Finally, she added, only two of the pledge’s 31 words are religious in content.

Although the court’s dismissal of the Newdow case means that Justice O’Connor’s concurrence has no direct legal effect, her opinion is still significant because some court watchers predict that if the current court were to consider ceremonial deism again, swing-voter Justice Anthony Kennedy might join the four more-liberal justices in adopting O’Connor’s proposed ceremonial deism test. If the court were to adopt her test, the most common official references to religion, such as the national motto and Pledge of Allegiance, would seem secure. In contrast, more particular religious references, such as legislative prayer in the name of Jesus Christ, might rest on weaker constitutional footing.

This report was written by Jesse Merriam, Research Associate, Pew Forum on Religion & Public Life; Ira “Chip” Lupu, F. Elwood and Eleanor Davis Professor of Law, The George Washington University Law School; and Robert Tuttle, David R. and Sherry Kirschner Berz Research Professor of Law and Religion, The George Washington University Law School.

Photo credit: Kevin Lamarque/Reuters/Corbis