By the time the 139th annual convention of the Episcopal Diocese of Pittsburgh concludes Saturday afternoon, the following scenarios could loom in the near future:

The diocese begins charting a withdrawal from the Episcopal Church USA to become part of the Anglican Church of Uganda; or

Liberal members ban together in opposition to perceived schismatic actions and petition the national church's presiding bishop to reconstitute the diocese and appoint a new bishop; or

The diocese remains in an uneasy holding pattern pending various future meetings of national and international denomination leaders.

The third possibility is most likely. But given the fractiousness within the Pittsburgh diocese, the rest of the country and the worldwide Anglican Communion, anything is possible.

The convention will be held tomorrow at the Embassy Suites in Moon and on Saturday at nearby St. Philip Episcopal Church.

Primary on the convention agenda are two proposed constitutional amendments, the most important of which would give the Pittsburgh diocese say over which national church laws and provisions it would follow.

There's enough interest in what happens that the Episcopal News Service plans to cover the proceedings.

The reason is the "s" word: schism.

The more than 70-million-member Anglican Communion has been dogged by that very possibility over the issues of gay ordination and same-sex blessings. Even the release last month of the Lambeth Commission's Windsor Report, which castigated the church's liberals and conservatives for their handling of human sexuality issues, did little to lessen such talk.

Pittsburgh Bishop Robert W. Duncan Jr., who is the leader of the Anglican Communion Network of dioceses and parishes that has been at odds with Episcopal Church leadership, said he didn't expect any precipitous actions during the diocesan convention.

"What we will be doing during our convention is simply affirming what the rest of the communion believes," said Duncan, who heads one of the Episcopal Church's most conservative dioceses. "We're not going to implement things beyond the scriptural witness of the church."

But he said he views the national Episcopal Church as "melting away" from its traditional beliefs, and that "an extraordinary realignment, rearrangement and reformation is under way."

The first proposed amendment, which will be discussed tomorrow and whose passage is virtually guaranteed, would declare that if the diocese's constitution or canons differ from those of the national church, "the local determination shall prevail."

Some observers believe the amendment -- Article I, Section 1 -- could be a prelude to the diocese separating from the Episcopal Church, but at least two other dioceses have passed similar amendments in the past with no such results.

Adding to the speculation is the fact that the Most Rev. Henry Orombi, the Archbishop of Uganda, will attend the convention as keynote speaker. In mid-August, Orombi agreed to provide oversight for three parishes that decided to leave the Diocese of Los Angeles.

Joan Gundersen, a scholar of Episcopal Church history and vice president of Progressive Episcopalians of Pittsburgh, believes the proposed amendment not only "is beyond the power of the diocese to enact" but also is illegal according to church canon.

The second proposed amendment, Article III, Section 2, would delete a requirement that clergy voting in diocesan conventions must be actual residents of the diocese as well as canonical residents. It, too, is expected to pass. Both proposed amendments will be decided by a roll-call vote.

A further example of the diocese's growing distance from the national church is evident in the budget figures that will be discussed at the convention.

Allocations to the national church for 2004 and 2005 are listed as zero, a fallout from the church's consecration of openly gay Bishop V. Gene Robinson of New Hampshire last year. In 2003 and 2002, the diocese contributed more than $123,000 each year to the national church.