IT IS IMPOSSIBLE TO UNDERSTAND RELIGION IN AMERICA without understanding American religious freedom. That freedom is defined in large part by the first amendment to the United States constitution. The first amendment states: Congress shall make no law respecting an of religion, or prohibiting the exercise thereof; or abridging the freedom of speech. . . .Let me begin by offering a very basic review of these clauses and their application. The first clause is the establishment clause; it prohibits the government from promoting a particular religion or religion in general. The second clause is the free exercise clause; it traditionally has prohibited the government from interfering with the religious practice of citizens and groups. The third clause is the free speech clause, a clause the United States supreme court has often relied on to protect citizens' rights to express their faith. In a nutshell, these clauses prohibit the government from promoting religion, but they also oblige the government to protect the right of religious individuals and groups to practice their faith, both in private and in public spaces.1How do these constitutional principles apply in various settings? In public schools, for example, the US supreme court ruled in the 1960s that the ban on governmental promotion of religion prohibited school teachers from leading their classes in prayers and Bible readings. But these rulings leave room for students to pray and read the Bible at school as well as to form religious clubs in public secondary schools on the same basis as they form other non-curriculum-related clubs, such as chess clubs or scuba-diving clubs.2Under our constitution, the government cannot erect or sponsor displays that lack a secular purpose and primary effect. To cite one prominent example, when an Alabama judge recently placed a several-ton monument featuring the ten commandments in a courthouse lobby, a court found the display unconstitutional. But the supreme court has held that, when groups of citizens are generally permitted access to government parks, citizens wishing to hold religious rallies or carry religious symbols also must be permitted such access as long as it is clear that the government is not endorsing religion. So, while it is sometimes suggested otherwise, the US constitution does not require or permit the public square to be stripped of religious influence.3As for policy-making and politics, our constitution requires governmental action to have a non-religious purpose and primary effect but, within those parameters, religion may inform public policy. And religious organizations certainly enjoy the righr to speak out on public issues, just as other non-governmenral groups do.4It also is generally agreed thar our constitution affords government officials and political candidates a great deal of freedom to talk about their personal religious convictions. At the same time, many Americans would say that, while there is great freedom under the law to bring religious talk into the political realm, there are also serious ethical and religious responsibilities when one does so. A favorite admonition of mine is one offered by the lace Barbara Jordan, an African-American congresswoman, who said that, when we speak of religion in the public square, we should remember that we are God's servants, not God's spokespeople.5 Humility is an essential ingredient when mixing religion and public affairs.Legal restrictions in the area of American policy-making and politics flow not only from our constitution, but also from our tax code. For example, tax-exempt groups organized under Section 501(c)(3) of our tax code, including churches and many other religious organizations, are prohibited from endorsing candidates for elective public office if they intend to maintain that tax-exempt status.6What about government funding and religious institutions? This area of the law is complex, evolving, and controversial, so it is difficult to describe simply or briefly. …