Is there any difference between a teacher making kids sing religious songs or political songs?
Not really. No matter how you view politics, I hope you would agree with me when I say that neither are appropriate in public schools. By forcing children to sing a religious song, you are infringing upon the child’s (and the parents’) first amendment right, specifically about freedom of religion. On the other hand, by forcing a child to sing a political song, you are again infringing upon the child’s first amendment right (and the parents’, as well), because you are more or less signaling that if they do not agree with the specific view, then the child is wrong in his/her beliefs. While this isn’t as clear cut and obvious as religion in public schools, it still is an infringement on a student’s rights.