Interesting interview with Father David Endres, assistant professor of Church history and historical theology at The Athenaeum of Ohio.
CNA: In 1922, Oregon passed a law forcing all children between the ages of eight and sixteen in parochial and private schools into public schools. The law, the Compulsory Education Act of 1922, was supported by the Ku Klux Klan as a measure to push for standard American education and to prevent what they saw as a foreign influence – the Catholic Church – from educating immigrant children.
The Society of Sisters of the Holy Names of Jesus and Mary, along with a military private school, fought the law in court. Three years later, in Pierce v. Society of Sisters, the Supreme Court resoundingly struck down the law in a unanimous decision, ruling that it violated the freedom of parents to send their children to parochial schools. More on this here.