Church rejects women bishops
More than 100 members spoke during six hours of discussion in a vast circular chamber in Church House, the Church's central London headquarters, airing their views under a domed ceiling inscribed with a prayer to "them that endured in the heat of conflict".
The dispute centred on ways to designate alternative male bishops to work with traditionalist parishes that might reject the authority of a woman bishop named to head their diocese.
Conservative evangelicals and Anglo-Catholics argue that a male-only clergy is God's will or say that ordaining women bishops would break with the tradition of the male-only clergy that stretches back to the Twelve Apostles.
Bishops are crucial senior managers in Christian churches that uphold the episcopal tradition because only they can ordain priests and assure the continuation of the clergy.
Dr Welby, an experienced conflict negotiator, drew the loudest applause when he urged members to compromise and vote for the measure, citing bloody conflicts in the Middle East and Africa as examples of what intractable differences can lead to.
"At this very moment in places from Israel and Gaza to Goma in the Congo, there is killing and suffering because difference cannot be dealt with," he said.
"We Christians are those who carry peace and grace as a treasure for the world. We must be those who live a better way, who carry that treasure visibly and distribute it lavishly."
However, opponents said the legislation could not be passed in its current form. Lay member Jane Patterson urged the Synod not to "bow to cultural pressure", warning more priests would defect to the Roman Catholic Church if the law were passed.
"England cannot afford this loss if we're serious about sharing the Gospel with the nation," she said.
About 60 traditionalist clergy, including five male bishops, and about 900 lay members have already switched to the Roman Catholic Church after Pope Benedict welcomed those who had become alienated by the prospect of the changes.
The structure of the Synod means a "no" vote puts off the proposed reforms for at least another five years, extending the acrimonious debate.
Religion commentator Peter Ould, an Anglican priest, said Welby's work in conflict resolution should stand him in good stead in attempting to resolve the emotive issue.
"This is a guy who's gone off to Nigeria where he was nearly kidnapped and killed trying to bring conflicting parties together - I think he can handle the Church of England," he said.
Each of the 44 member churches in the worldwide Anglican Communion can decide for itself whether to allow women bishops.
Many Anglicans in developing countries are strongly opposed to women priests, no less bishops, and many national churches there have formed a parallel group to the Communion to coordinate their efforts against reforms they see changing Anglican churches in the West.