Because Monday is the federal Birthday of Martin Luther King Jr. holiday, the change will not take effect until Tuesday, the Chicago Tribune reported.
U.S. District Judge Robert Gettleman, who issued a temporary injunction on the Illinois Silent Reflection and School Prayer Act two years ago, lifted it Thursday, the state Board of Education said. A federal appeals court found the law constitutional four months ago.
The U.S. Supreme Court banned school prayer in the 1960s. Critics say moment of silence laws are a way to reintroduce religious observance in schools in violation of the First Amendment.