@Elmud,
In fact you can not force someone to take/recite any kind of an oath, or any kind of prayer in public school. That includes the national anthem.
The more subtle problem is public displays of religous symbols or the voluntary recitation of the pledge of allegiance, students right to wear religious jewelry or publically pray, the right of religious groups to use public faciitiies, schools, etc.
The right of public officials to use religious language.
Separation of church and state should not mean supression of voluntary religous observance.