WASHINGTON -- The Rev. Robert Duncan, 60, is not a Lutheran, but he is a Luther, of sorts. The former Episcopal bishop of Pittsburgh has, in effect, said the words with which Martin Luther shattered Christendom and asserted the primacy of individual judgment and conscience that defines the modern temperament: "Ich kann nicht anders" -- I cannot do otherwise.

The Episcopal Diocese of Pittsburgh recently became the second diocese (the first was in Fresno, Calif.) to secede from the U.S. Episcopal Church since, but not entirely because of, the 2003 ordination in New Hampshire of an openly gay bishop -- Gene Robinson, a classmate of Duncan's at General Theological Seminary in New York in the 1970s. Before the Robinson controversy, other Episcopalians, from South Carolina to Southern California, had disassociated from the Episcopal Church and put themselves under the authority of conservative Anglican bishops who serve where the church is flourishing -- often in sub-Saharan Africa, where a majority of Anglicans live.

It is not the secessionists such as Duncan who are, as critics charge, obsessed with homosexuality. The Episcopal Church's leadership is latitudinarian -- tolerant to the point of incoherence, Duncan and kindred spirits think -- about clergy who deviate from traditional church teachings concerning such core doctrines as the divinity of Christ, the authority of scripture and the path to salvation. But the national church insists on the ordination of openly gay clergy and on blessing same-sex unions.

In the 1960s, Bishop James Pike of California, who urged the church to jettison such "theological baggage" as the doctrines of Original Sin and the Trinity, was the last active bishop disciplined for theological reasons. Duncan doubts whether Pike would be disciplined today.

Duncan became a bishop in 1995, at age 47, in an Episcopal Church already roiled by dissension about the ordination of women, revision of the prayer book and other matters. But, Duncan says, "I wish it" -- the issue that finally precipitated secession -- "had been some other issue." He means some controversy, other than Robinson's ordination, turning on scriptural authority.

The shrinking Episcopal Church (2.4 million members, down from 3.5 million at its peak in 1965) is a small sliver of the worldwide Anglican communion (at least 77 million and expanding rapidly). Its travails are, Duncan says, yet another lingering echo of the 1960s.

The Anglican communion once was a "via media," a middle way, between Catholicism and Protestantism. Now, Duncan says, the national leadership of the Episcopal Church thinks of itself as a bridge between Protestantism and the culture. Duncan and other protesters agree with the late Flannery O'Connor, the Catholic novelist: "You have to push as hard as the age that pushes against you."

Every 10 years there is a Lambeth Conference of Anglican bishops, presided over by the archbishop of Canterbury. This year only 650 of the nearly 900 bishops attended -- 150 of them representing only the tiny U.S communion. The bishops from three of the Anglican communion's five largest provinces -- Nigeria, Uganda and Kenya -- boycotted.

Today, the typical Anglican is a middle-aged African woman. The burgeoning Nigerian church says it has 20 million Anglicans; Duncan believes it may have 25 million but perhaps chooses to underreport so as not to exacerbate tensions with Nigerian Muslims.

In London, more Muslims attend Friday prayers than Anglicans attend Sunday services. Last December, on the Sunday after former Prime Minister Tony Blair was received into the Catholic Church, more Catholics than Anglicans attended services in England, an increasingly common occurrence now, five centuries after the Reformation.

"I think," Duncan says, "the 21st century will be for the archbishop of Canterbury what the 20th century was for the royal family." That is, an era of diminution.

Because Protestantism has no structure of authority comparable to the Vatican, and because it does not merely tolerate but enjoins individual judgments by "the priesthood of all believers" concerning beliefs and obligations, all Protestants are potential Luthers. Hence it is evidence of spiritual vigor that Episcopalians in Quincy, Ill., and Fort Worth, Texas, will vote on disassociation from the U.S. communion on Nov. 7 and Nov. 14, respectively.

The Episcopal Church once was America's upper crust at prayer. Today it is "progressive" politics cloaked -- very thinly -- in piety. Episcopalians' discontents tell a cautionary tale for political as well as religious associations. As the church's doctrines have become more elastic, the church has contracted. It celebrates an "inclusiveness" that includes fewer and fewer members.