Debates over the role of religion in public schools have roiled our nation for a long time. Public schools must educate children from a wide variety of religious beliefs as well as those who are non-religious. They can’t do that if the schools are promoting certain faiths.

Seventy years ago today, the U.S. Supreme Court took a giant step toward reinforcing that principle when it handed down a ruling in an important case called McCollum v. Board of Education.

The 8-1 decision ended a practice in the Champaign, Ill., public schools of allowing ministers to come onto the campus during the day to offer sectarian instruction. The ruling is crucial because it marked the first time the high court declared that our public schools could not be in the business of promoting religion to students. It paved the way for the 1962 and ’63 rulings striking down official school prayer and Bible reading.

Writing for the majority in McCollum, Justice Hugo Black scored “the use of tax-supported property for religious instruction and the close cooperation between the school authorities and the religious council in promoting religious education.”

Black added, “Here not only are the State’s tax-supported public school buildings used for the dissemination of religious doctrines. The State also affords sectarian groups an invaluable aid in that it helps to provide pupils for their religious classes through use of the State’s compulsory public school machinery. This is not separation of Church and State.”

The family behind the case was led by a strong-willed matriarch named Vashti McCollum. Vashti knew taking on this case would not be easy – and it wasn’t. But she also knew it was the right thing to do. Vashti examined the materials that would be taught in the religion classes and recognized them for what they were: efforts to proselytize. She declared that her son Jim would not take part.

Jim was in fifth grade at the time, and he was the only kid not taking the course. He was singled out for that and left to sit alone in a tiny room. On occasion, he and his brother Dannel were bullied by other students. Teachers constantly pressured Vashti to change her mind. Things got so bad that Vashti and her husband John sent Jim to live with relatives in New York for a while.

The family was plagued with harassing phone calls and threatening mail. On Halloween of 1945, some hoodlums knocked on the family’s door, and when Vashti answered, she was pelted with rotten fruit and vegetables. Someone killed the family’s cat.

Other forms of retaliation were more subtle but equally painful: Vashti, who had been working as a physical education instructor at the University of Illinois at Champaign, was abruptly terminated. John, who also worked as an instructor at the university, saw his career stall.

Nevertheless, the McCollums persisted. They litigated the case in state court and lost twice there. The matter then went to the U.S. Supreme Court, which reversed the lower court rulings. The ruling was one of the high court’s first opportunities to expound on church-state separation as it applied to public schools and is today recognized as a landmark decision.

Vashti died in 2006 at the age of 93. She had remained active in church-state causes all of her life. Jim McCollum went on to law school and helped form Americans United chapters in New York and Arkansas. He remains involved in the fight to maintain church-state separation. (Vashti and Jim were given Religious Liberty Awards by Americans United in 1995.) Dan McCollum wrote a book about his experiences titled The Lord Was Not On Trial and entered politics, serving as mayor of Champaign from 1987-99. In 2010, PBS aired a documentary about the case.

The McCollum family’s brave stand helped pave the way for public schools that are open to young people of all faiths and none. Their activism has ensured that our public schools remain focused on secular education, not religious indoctrination.

They deserve the thanks of all Americans.