Washington ? Even people of different faiths, and of none, should watch the results of the London meeting, ending today, of the 38 Anglican primates convened by Rowan Williams, Archbishop of Canterbury and titular head of the 75-million-member Anglican Communion worldwide. The meeting is part of a drama rich with lessons about the conservation of institutions, the price of “progressive” cultural aggression and the changing geography of religious belief.

Episcopalians, the American adherents of Anglicanism, were once a formidable cultural force — the American establishment at prayer. But after years of pursuing communicants with political and cultural trendiness rather than doctrinal clarity, Episcopalianism is a small and dwindling faction of American Christianity — “a flea on the American religious landscape, and yet we always seem to attract more attention than we deserve,” according to one bishop. Membership is down 33 percent, to 2.3 million, since 1965. As the noted Catholic priest Ronald Knox wrote 75 years ago, “Dogmas may fly out at the window but congregations do not come in at the door.”

On Aug. 5 the faction’s tenuous unity was shattered when one doctrine too many flew out the window. The church’s General Convention, meeting in Minneapolis, voted to confirm as New Hampshire’s bishop a noncelibate gay priest. Church “progressives,” ignoring conservatives’ warnings of serious consequences, and having had their way on such matters as prayer book revision and ordination of women, were again calling the conservatives’ bluff.

This time the conservatives are not bluffing. And they are ardently backed by primates from what is called the Global South, representing the vast majority of Anglicans — in Latin America, Asia and especially Africa. For example, Bishop Peter Akinola of Nigeria, a fierce opponent of the Minneapolis decision, represents 17.5 million Anglicans.

A leader of American conservatives, the Rev. David Anderson, president of the American Anglican Council, says: “It’s like when you pull the cadmium rods out of a nuclear core. You take some out and nothing happens. But you reach a point where you reach critical mass and you have an explosion.” Of the fallout from Minneapolis, Anderson says, “the presenting symptom is sex, but that is not the issue.” The issue is “the loss of Biblical authority.”

Advocates of the gay bishop argue the way some Americans do when finding new rights and social-policy imperatives in a limitlessly elastic “living Constitution.” The bishop’s advocates say Scripture and 2,000 years of church teaching about sexuality and family are being “imaginatively construed in a certain interpretive trajectory.” The Rev. Martyn Minns of Fairfax, Va., an opponent, says that in Minneapolis, “When the plain teaching of the Bible was referenced, eyes rolled, and with expressions of polite exasperation we were told that it was time to move on. The Bible simply hadn’t kept up.”

Two weeks ago, when Williams visited John Paul II, the pope said the Minneapolis decision presented “new and serious difficulties” to ecumenical efforts. And when 2,700 conservative Episcopalians met last week in Dallas to urge the London meeting to give them relief, they received an extraordinary letter of support from the Vatican — from Cardinal Joseph Ratzinger, speaking on behalf of the pope.

The Queen regards Anglicanism as the glue holding together the Commonwealth. The Global South bishops reportedly have written to her and she may have made known to Williams an anxiety he should share — that he and the Church of England could become irrelevant to an Anglicanism in which leadership would be exercised from, say, Nairobi.

In Dallas, Robert Duncan, Bishop of Pittsburgh, warned that the Archbishop of Canterbury could become “little more than the titular head of a moribund and declining British, American and Australian sect.” Although the office of Archbishop of Canterbury dates from the sixth century, its holder has no power to impose uniformity on matters of faith and practice over Anglicanism’s autonomous provinces. However, he can broker a resolution satisfactory to the angry majority of primates, who represent Anglicanism where it is expanding.

In Africa and other places where Christianity competes with militant Islam and other fighting faiths, bishops are, says Anderson, “battleground Christians” who have seen Christians “have tires put around their necks and set on fire. You can’t cow them.” Or bribe them. Those bishops are furious about what they consider the liberal imperialism of Western churches trying to wield cash coercively against theologically conservative but financially weak churches in the Global South.

They will insist on discipline, perhaps even on disenfranchisement of the American church, replacing it with what they consider the orthodox remnant of American Episcopalians. In a few days, some institutional work of centuries may be undone.

George Will is a columnist for Washington Post Writers Group.