[Matthew Dennis, professor of history at the University of Oregon, is the author of "Red, White, and Blue Letter Days: An American Calendar."]

Since the beginning of the republic itself, the role of religion in American life has been controversial - even as the United States supposedly became a more secular society, and even in Oregon, statistically the least churched state in the union.

A case in point is the annual Eugene-Springfield Mayors' Prayer Breakfast, the subject of an April 10 column by Rabbi Yitzhak Husbands-Hankin. The local event is an example of a larger phenomenon, which includes annual mayors', governors' and even presidential prayer breakfasts. Many occur on the official National Day of Prayer on the first Thursday in May. This year that falls on May 5 and competes with an altogether different occasion, Cinco de Mayo, a celebration of diversity....

The roots of the Mayors' Prayer Breakfast go back to the early 1950s, in the context of the Cold War, when a joint resolution of Congress, signed by President Harry Truman, declared an annual National Day of Prayer. This was the era in which "under God" was spliced into the Pledge of Allegiance. In 1953, President Dwight Eisenhower presided over the first National Prayer Breakfast in Washington, D.C. Soon prayer breakfasts multiplied and became fixtures in state capitals and other communities across the country, sometimes set for the National Day of Prayer and sometimes held on other dates.

Despite the participation of public officials and their public prominence, the breakfasts are technically private, not official, government-sponsored events. Therefore, they usually manage to avoid charges that they violate the constitutional doctrine of the separation of church and state.

Still, it's easy to see the confusion that such not-quite-official events create. Particularly when prayer breakfasts are more stridently sectarian, like the one that Rabbi Husbands-Hankin experienced last year, they convey a message - not simply that one faith community is praying for public leaders, but that the U.S. is one nation under a particular God, and that this particular religion has special governmental access and authority. Implicit endorsement by public officials through their participation lends powerful weight to such exclusionary messages.

In some communities, prayer breakfasts are broadly inclusive, reaching out to various Christian denominations, Jews, Muslims and others. In most places, they are not.

The Central Florida Mayors' Prayer Breakfast Web site explains, for example, that its event "is held in the belief that only God's guidance and inspiration can provide optimum leadership for the people, our cities, states, nation and world."

Whose God do they mean?

A prominent link takes browsers to the Ministry & Prayer Request Card, available at the breakfast, to request more information "on Christian life" and "a personal relationship with Jesus Christ." One can check a box to indicate, "I have received Jesus Christ as my Personal Savior ... at this breakfast ... (or) Recently."

Such sectarianism has inspired criticism, not merely from nonbelievers and non-Christians but from Christians as well....

Controversy will no doubt continue as Americans debate "under God," spend coins inscribed "in God we trust," open court sessions with religious invocations, and eat breakfast amid Christian prayers and proselytizing implicitly sanctioned by public officials. Since Gov. George W. Bush's proclamation in 2000, there has been a Jesus Day in Texas and in other states as well. Religion endures in American life.

Yet, ironically, American religion's health depends not on its ability to force its way into official status but on the protection all faiths receive by allowing no particular faith to dominate. In short, we all benefit by giving currency to the First Amendment and to the motto, E Pluribus Unum.