The Constitution in its historical context was designed to protect both Protestantism and Catholicism, but it was never designed to protect Islam.The Constitution protects free religious exercise except where Establishment is being violated. Where precisely in the Constitution is "religion" defined in a manner which excludes Islam?
It should be noted that two years before the Constitution was signed, the Virginia Act For Religious Freedom was debated. There was an effort to make it only apply to Christians. One of the more influential delegates objected to this idea.
Who does not see that the same authority which can establish Christianity in exclusion of all other religions may establish, with the same ease, any particular sect of Christians in exclusion of all other sects? That the same authority which can force a citizen to contribute threepence only of his property for the support of any one establishment may force him to conform to any other establishment in all cases whatsoever?
When one considers that this particular delegate ended up being considered the primary author of our Constitution, logic does not support the idea that said document protects solely the Christian denominations. Therefore, the comparision of anti-Catholic bigotry at the dawn of the 20th Century and anti-Islamic bigotry at the dawn of the 21st retains its validity.
-Eric
As I'd argue it, the key point at issue is what the Constitution means by "religion" in the phrase "establishment of religion". The context of this phrase includes the wider context of the Declaration of Independence, which opens with references to "the Laws of Nature and of Nature's God" and to men being "endowed by their Creator with certain unalienable Rights". This, as may be verified in the writings of the framers of the Constitution, is referring to the 18th-century concept of natural law and the underlying tradition of natural rights extending back through John Locke to Thomas Aquinas, Augustine, the Sermon on the Mount, and ultimately, the Ten Commandments. In this tradition the Ten Commandments and the Golden Rule are considered to embody certain principles which are the foundation of a just social order. These principles are common to Judaism and Christianity and are alluded to in the Declaration of Independence's phrase "unalienable Rights", which are the "Rights" the "Bill of Rights" is enumerating. This is not excluding non-Christian religions (cf. my Post #24); it is, however, excluding religious practices based on principles which radically depart from the principles common to Judaism and Christianity that derive from natural rights (thus, for instance, to take an extreme example, the Constitution would not protect a religious practice involving ritual murder). Also, the Bill of Rights is addressing states' rights issues and protecting the right of individual states not to have their established religions infringed upon by the federal government (keep in mind that the states originally had established religions), whereas the legal argument in the case in question is attempting to have the federal government impose Islam on a non-federal level of the educational system. Note that I am not arguing the Constitution only protects Christianity; I am arguing that Judaism and Christianity are the paradigm of what the Bill of Rights protects, and when Islam attempts to claim rights which step outside that paradigm, it steps outside the protection of the Constitution. Christians do not have a Constitutional right to violate school dress codes--why should Islam?