A decades-long culture war over the relationship between government and religion and the role of faith in civil society shows no sign of abating. New cases are coming before the Supreme Court, and fresh conflicts are arising over the placement of religious displays on public property and the use of government money to support faith-based social-service programs. At the heart of the battle lies the question of whether the United States was formed as a "Christian nation" -- as many conservatives contend -- or whether the Founding Fathers meant to build a high wall of separation between church and state. President Obama outraged conservatives when he declared, "we do not consider ourselves a Christian nation or a Jewish nation or Muslim nation" but a "nation of citizens who are bound by ideals and a set of values." Still, the share of Americans who profess to be Christians has been shrinking, while the percentage who claim no religious preference has nearly doubled since 1990.

Thomas J. Billitteri is a CQ Researcher staff writer based in Fairfield, Pa., who has more than 30 years' experience covering business, nonprofit institutions and public policy for newspapers and other publications. He has written previously for CQ Researcher on "Domestic Poverty," "Curbing CEO Pay" and "Teacher Education." He holds a BA in English and an MA in journalism from Indiana University.