Massachusetts’ highest court will hear a case that may permanently strike the phrase “under God” from the Pledge of Allegiance in the state’s schools.

Two weeks ago, attorneys representing an unidentified atheist family from the Acton area filed a brief that argues that the phrase “under God” is an endorsement of a religious world view.

The American Humanist Association, a secular rights group, has joined the case, asserting that the phrase “under God” violates the equal rights amendment in the Massachusetts Constitution. The group also argues that daily recitation of the Pledge of Allegiance in the classroom counts as unlawful discrimination.

Together, the school district and the Acton-Boxboro Superintendent, Stephen E. Mills, are acting as one defendant in the case. A Catholic family, Daniel and Ingrid Joyce, have been joined by the Knights of Columbus, as a second defendant group. The Becket Fund for Religious Liberty represents the latter group.

Eric Rassbach, deputy general counsel for the Becket Fund, said that the “God” referred to in the pledge is the origin of the rights of Americans, not a religious deity.

“They wanted to draw a distinction between countries like the Soviet Union, where rights proceed from the state,” Rassbach said. He added that the Declaration of Independence demonstrates that the founding fathers believed rights come from the creator, and that the government can’t take them away.

The phrase “under God” was inserted into the pledge in 1954, with the encouragement of President Eisenhower, as part of an effort to distinguish the United States from the Soviet Union, which was openly atheistic.

Rassbach said that he expects prior federal court rulings, which have kept “under God” in the pledge, to prevail in the current case, since it is illegal to punish students who wish not to recite the pledge or who prefer not to say the words “under God.”

“The question is if they cannot force other people not to say the pledge in their presence,” said Rassbach. “We don’t think it’s good for religious liberty if the word God has to be put under quarantine.”

Oral arguments will begin in early 2013. A judgment should be delivered by early summer.