Roll Over, Martin Luther

Benchmark statistical moments are almost always anticlimactic. When the U.S. population shifted from rural to urban areas in 1920, there was no annunciatory thunderclap. And in about 2060, the year by which census figures suggest that non-Hispanic whites will become less than 50% of the population, the switch will have long been old news. Still, such dates have historical cachet, and 2004 soon may too. The University of Chicago's respected National Opinion Research Center (NORC) has reported that the proportion of adult Americans calling themselves Protestants, a steady 63% for decades, fell suddenly to 52% from 1993 to 2002. Not only that, the study's authors projected that "perhaps as early as this year the country will for the first time no longer have a Protestant majority." The heads-up provoked some spirited discussion about how important the eclipse might be, to whom, and why. Here are the key questions:

--IS EVERYTHING SUDDENLY DIFFERENT? Hardly. As Boston College political scientist Alan Wolfe notes, "Even if Protestants dip below 50%, they're still twice as large as any other group. They're always going to be the largest group, ever, of anybody." But looking at the past, he admits this is a "big deal. John Jay wrote in the Federalist papers that we were united by a common religion. But based on this survey, you can't say that these days."

--ARE WE LOSING PROTESTANTS OR SIMPLY FLOODED WITH NON-PROTESTANT IMMIGRANTS? The latter has been suggested, disapprovingly, by Harvard political scientist Samuel Huntington. But NORC STUDY CO-AUTHOR TOM W. SMITH SAYS, "immigration is a factor, but it's not the major thing." More important are a falling away of adult believers and a declining number of Protestant children who keep the faith. The Catholic proportion of the population has held steady at 23%. Neither Jews nor Muslims top 4%. The category that has really jumped (from 8% to 14%) in the past decade is people who say they don't subscribe to any religious identification. Most of this group aren't Atheists, say scholars like Claude Fischer at the University of California, Berkeley. They still believe in basics like God, heaven and the bible as an inspired text, but prefer to think of themselves as spiritual rather than anything more specific.

WHO IS MOST AFFECTED BY THE PROTESTANT SWOON? Primarily the more liberal mainline denominations like United Methodists, the Presbyterian Church (USA) and the Episcopal Church. "We are losing our own children," says Kenneth Carder, Bishop of the Methodists' Mississippi Conference. But even some evangelical growth is tapering: the 16.3 million-member Southern Baptist Convention has conceded a drop-off in Sunday school enrollment.