In 1948 the Supreme Court (8-1) held invalid under the 14th Amendment a system adopted by the Illinois Board of Education which permitted students, on written request of their parents, to be released during regular school hours for religious instruction or devotion in the public school buildings. McCollum v. Board of Education 333 U.S. 203, 2 A.L.R. 2d 1338 (1948). Under these so-called "released time" plans, non-participating children remain in the classroom and continue some form of secular study. Since the majority opinion in the McCollum case relied in part upon the metaphorical "wall of separation between Church and State," an uncertain test was provided for the future disposition of systems distinguishable from that involved in the Illinois case. The constitutional vice in the McCollum plan could have been the use of public money and property for religious purposes, or more broadly, the coercive effect of the plan in that the children released from the classroom routine to the religious services were still satisfying the statutory obligation to attend school.
Raymond H. Siderius,
Constitutional Law—Fourteenth Amendment—Religious Education—Validity of Released Time Programs,
28 Wash. L. Rev. & St. B.J.
Available at: https://digitalcommons.law.uw.edu/wlr/vol28/iss2/7