The ratification of the 18th Amendment banning the manufacture, transportation or sale of alcoholic beverages had obvious implications for Catholic priests and Jewish rabbis, as well as for tavern owners. Thus, legislators wrote an exemption into the bill that defined the Prohibition era allowing the sacramental or medicinal use of alcoholic beverages. The wine on Catholic altars and Jewish Seder tables remained real -- thanks to the Volstead Act's fine print.

"If the act had failed to exempt wine for sacramental purposes there would have been both a political firestorm and a First Amendment challenge," noted William Galston of the Brookings Institute, at a recent religious-liberty conference in Washington, D.C.

This is not dusty history, in a year loaded with tense clashes between religious groups and the government. Thus, Galston said it's important for politicians and clergy to remember 1919 and to ask, "Would that challenge have succeeded? This is not a peripheral issue. The use of sacramental wine lies at the heart of more than one religion."

Truth is, the timeline of American history is dotted with similar conflicts. While the First Amendment offers strong protections, politicians and judges have frequently tweaked the boundaries on the religious-liberty map.

Several church-state fires are currently burning, including intense debates linked to health care as well as to same-sex marriage.

Many speakers during the conference, which was sponsored by the American Religious Freedom Program of the Ethics and Public Policy Center, focused on conservative concerns about the impact of new Health and Human Services regulations. The key is that these mandates require the health-insurance plans offered by most religious institutions to cover sterilizations and all FDA-approved forms of contraception, including "morning-after pills" -- even when this violates ancient doctrines.

As a former domestic policy adviser for President Bill Clinton, Galston knew that he wasn't "preaching to the choir" when telling conservatives that today's conflicts are not unprecedented and have been inflamed by the "overwrought polemics" of contemporary politics.

No matter what the headlines say, Galston said he believes Catholic bishops are not "conducting a war on women and the Obama administration is not conducting a war on religion. There is, instead, a genuine disagreement over the respective roles of religious obligation and civil law. This disagreement takes place against the backdrop of an enduring fact -- there is no guarantee that the requirements of citizenship and of faith will prove fully compatible in a religiously diverse and non-theocratic society."

In addition to the Prohibition Era conflict, it's easy to spot similar clashes in American life -- past and present.

For example, noted Galston, the U.S. government "mercilessly hounded" the Mormon Church for decades and in the early 20th century anti-Catholic forces made serious attempts to outlaw parochial schools. In 1990, the U.S. Supreme Court ruled that Native Americans could be denied the right -- required by centuries of tradition -- to use the drug Peyote in religious ceremonies.

There's more. During his White House years, Galston said he often had to inform delegations of Christian Scientists that "federal laws on child abuse and neglect trumped their conscientious beliefs as to the form of medical care that their children should receive."

The U.S. Supreme Court has proclaimed that religious groups are not allowed to violate "common community conscience" on racial issues, even when acting for doctrinal reasons. Thus, Bob Jones University lost its tax-exempt status in 1983 because of what it then proclaimed were Bible-based policies forbidding interracial dating.

A key issue today is whether this civil-rights standard will soon be applied to gay rights, noted Galston.

"Many religious organizations take the position that opposing same-sex adoption cannot be equated with opposing comparable interracial activities," he said. "In law, that is mostly correct -- for now. But some states have already moved to settle the issue in favor of same-sex couples and more ... are likely to follow."

Can this conflict be resolved? History says there is no easy answer to that question, said Galston.

"There is no guarantee that public opinion will converge on what justice requires. The conscience of the community has often erred and will continue to do so," he said. "There are compelling reasons within modern states to carve out protected spaces for dissenting moral voices. But in the end, the tension between the laws of the state and the demands of faith cannot be fully resolved -- it can only be managed."