The following two clauses from the First Amendment pertain to schools:

The Establishment Clause prohibits the mandatory establishment of religion, ​while the Free Speech Clause guarantees the right to the free exercise of religion.

ESTABLISHMENT CLAUSE

The Establishment Clause states that schools cannot officially establish religion or even nonreligion (such as atheism).

​It only pertains to teachers and school staff, not to students. 

Most people are more cognizant of ACLU lawsuits than of student rights.  However the ACLU primarily focuses on mandatory prayer or religious symbols displayed in schools not on voluntary school clubs. In fact those faith-based clubs are fully acknowledged and endorsed even by the ACLU.  And, the ACLU has never challenged a christian school club in court and due to numerous recent lawsuits won by students whose schools denied clubs, an increasing number of principals are focusing on protecting their students' rights to Free Speech.   

Free Speech Clause

The First Amendment's Right to Free Speech allows public school students free speech which includes the right to express their religious beliefs.  

Because teacher rights are much more limited than student rights most people get confused and they assume that the student rights are also limited. However students are not in a position of authority and could never officially try to establish religion in the school. Therefore they cannot violate the establishment clause and because of that it does not apply to students (or even to any non staff adults such as parents or pastors.) 

Voluntary clubs fall into the Free Speech Clause and are fully protected by the first amendment free speech rights. In fact it's the obligation of school administration that each of their students has the right to Free Speech. That's why thousands of administrators invite faith-based institutions to facilitate the process of guiding students toward success on a voluntary level. 

This is why the NEA, the Department of Education, the White House and 13 other federal agencies are calling upon faith-based organizations to get involved in their local schools.

Most children who attend the local church also attend the local school.  Parents are connected to both institutions.  What other local organization has such a direct link to the school?  

​On average there are 14 churches per school; and yet it's difficult to find churches to get involved in schools.    ​