George W. Bush is agonizing over his decision about federal policy on stem-cell research. And White House aides, meanwhile, are busily "backgrounding" reporters with tidbits designed to show that the president who normally prides himself on snappy management is consulting widely and thinking deeply on the subject.

For the inside-the-Beltway Washingtonians, it all makes for interesting reading, but for outside-the-Beltway Americans, there's not much reason to follow the circuities of Bush's pondering because, in effect, the decision has already been made for him. Nothing is going to stop the march of science on this issue, because nothing has stopped the march of science over the last four centuries.

To be sure, Bush has authority over whether federal money can be used for research on stem cells extracted from surplus embryos discarded by fertility clinics. But any decision that Bush makes is subject to review by Congress and the courts, and any presidential order, furthermore, must be interpreted and enforced by federal bureaucrats.

And all these stem-cell players are heavily influenced by the larger media and scientific culture, which is overwhelmingly supportive of untrammeled research. Of course, nothing Bush might decide will have any effect on privately funded stem- cell inquiry.

Arguing from a mostly religious perspective, anti-stem-cellers deem all such research to be immoral, and no matter what Bush decides, they will no doubt continue to push for an overall ban. But there's not much chance they'll succeed, because the correlation of forces between religion and science is so lopsidedly in favor of science.

One might ask: When was the last time that religion won a war against science? Religion and science are naturally hostile to each other, because, at bottom, they are two different approaches to understanding the world. For most of human history, when people wondered where they came from, or why the sun rose in the morning, or why they got sick and died, they would consult a holy text and get an answer that satisfied them. But then came science, which offered a different approach: Answers were no longer to be found in dogma or faith, but instead in the scientific method -- observation, hypothesis, verification.

This new approach to answering questions had one huge advantage: It could work the same way for different people, in different situations, at different times. One may seek spiritual inspiration in churches and temples built by theologians, but in the physical realm, people rely on machines and medicines built by scientists.

Indeed, the history of the modern era is the story of science displacing religion on important public policy issues. In the early 17th century, for example, the Italian astronomer Galileo suggested that the official Catholic position, that the Earth was at the center of the universe, was wrong; he was hauled before the Inquisition in 1633 and forced to say that he agreed with the certified "geocentric" dogma. But it wasn't long, of course, before the scientific, "heliocentric" view prevailed.

And so began what religious critics called "the dethronement of man." The old idea, that human beings were the focus of divine creation, gave way to the emerging reality that the whole of the Earth is a mere speck in the universe. And the dethronement of man was completed, in a sense, by the evolutionary theories of Charles Darwin, who argued that homo sapiens had evolved, alongside all other flora and fauna, up from the primordial muck.

In America, the decisive confrontation between those who clung to the Biblical tale of creation and those who embraced Darwin's theory of natural selection occurred in 1925; that was the year of the "monkey trial," in which a high school biology teacher, John Scopes, broke Tennessee law by teaching evolution in his classroom. Scopes was convicted, but the trial and accompanying media circus left Scopes' fundamentalist Protestant prosecutors looking like fools.

Today, the same two groups that lost the most epochal religion- vs.-science battles in the past -- conservative Catholics and conservative Protestants -- are leading the crusade against stem-cell research. Their argument is that such research takes the dethronement of humanity to a new extreme; it destroys a human soul. And maybe it does.

But religion has been losing to science for centuries, and it's not likely that a single American president, obviously conflicted himself, is going to reverse, or even slow down, that trend.