Dr Williams, spiritual leader of the Anglican Communion, acknowledged the real possibility of the global body adopting a "two-track" model in which there would be "two styles of being Anglican".
Rather than a full-on schism, Anglicans in the 77 million-member body would try to work together while holding different theological convictions over such issues as homosexuality.
"It helps to be clear about these possible futures, however much we think them less than ideal, and to speak about them not in apocalyptic terms of schism and excommunication but plainly as what they are – two styles of being Anglican, whose mutual relation will certainly need working out but which would not exclude co-operation in mission and service of the kind now shared in the Communion," he wrote.
His reflections come nearly two weeks after The Episcopal Church approved two resolutions opening the ordination process to all baptised members, including practising homosexuals, and calling for the development of liturgical resources for the blessing of same-sex unions.
Episcopal Presiding Bishop Katharine Jefferts Schori has insisted that the resolutions do not repudiate the Church's relationships with other members of the Anglican Communion – who agreed on moratoria on consecrating partnered gays and blessing same-sex unions. But conservative Anglican leaders say the actions of The Episcopal Church – the US branch of Anglicanism – mark a clear break with the rest of the Communion.
While some conservatives argue that schism has already occurred within the third largest global Christian denomination, Dr Williams has continued to try and hold the global body together, particularly since 2003 when The Episcopal Church consecrated its first openly gay bishop.
He recognised that the US body's latest resolutions have again caused anxieties and conceded that the repeated request for moratoria "has clearly not found universal favour".
