The key question that faces the courts is whether the establishment clause should be understood as imposing, in Thomas Jefferson’s words, “a wall of separation between church and state.” In a 1971 case known as
Lemon v. Kurtzman , the Supreme Court established the Lemon test for deciding whether a law or other government action that might promote a particular religious practice should be allowed to stand.
1. The action or law must not lead to excessive government entanglement with religion; in other words, policing the boundary between government and religion should be relatively straightforward and not require extensive effort by the government.
2. The action or law cannot either inhibit or advance religious practice; it should be neutral in its effects on religion.
3. The action or law must have some secular purpose ; there must be some non-religious justification for the law.
For example, imagine your state decides to fund a school voucher program that allows children to attend private and parochial schools at public expense; the vouchers can be used to pay for school books and transportation to and from school. Would this voucher program be constitutional?
Let’s start with the secular-purpose prong of the test. Educating children is a clear, non-religious purpose, so the law has a secular purpose. The law would neither inhibit nor advance religious practice, so that prong would be satisfied. The remaining question—and usually the one on which court decisions turn—is whether the law leads to excessive government entanglement with religious practice. Given that transportation and school books generally have no religious purpose, there is little risk that paying for them would lead the state to much entanglement with religion. The decision would become more difficult if the funding were unrestricted in use or helped to pay for facilities or teacher salaries; if that were the case, it might indeed be used for a religious purpose, and it would be harder for the government to ensure that it wasn’t without audits or other investigations that could lead to too much government entanglement with religion.
The use of education as an example is not an accident; in fact, many of the court’s cases dealing with the establishment clause have involved education, particularly public education, because school-age children are considered a special and vulnerable population. Perhaps no subject affected by the First Amendment has been more controversial than the issue of prayer in public schools. Discussion about school prayer has been particularly fraught because in many ways it appears to bring the two religious liberty clauses into conflict with each other. The free exercise clause, discussed below, guarantees the right of individuals to practice their religion without government interference—and while the rights of children are not as extensive in all areas as those of adults, the courts have consistently ruled that the free exercise clause’s guarantee of religious freedom applies to children as well.