David Niose, who is representing a couple identified only as John and Jane Doe and the American Humanist Association, said the use of the phrase "invalidates atheists as unpatriotic," The (Lowell) Sun reported. The couple sued the Acton-Boxboro school district over the wording in the pledge.
After oral arguments, the Supreme Judicial Court said it would deliver its ruling later.
The pledge was written in 1892 by Francis Bellamy, who was both a Baptist minister and a socialist. It was adopted by Congress 50 years later and the phrase "under God" was added in 1954 during the Cold War.
In response to questions from the justices, Niose said allowing students to opt out of saying the pledge or saying "under God" would be "baby steps" in the right direction. But he suggested a rewritten pledge would be a better move.
Chief Justice Roderick Ireland pointed out that every court in Massachusetts begins the day with the phrase "God save the Commonwealth." Niose responded that he believes that use is "ceremonial."
Geoffrey Bok, the lawyer for the Acton-Boxboro schools, said he was not sure whether students are told they may opt out.