Ideas that might be harder for Anglicans to accept include the concept that the Pope is infallible, at least at certain moments, that Mary was the product of an "immaculate conception," and so born without sin, and the belief known as transubstantiation, which means, essentially, that the communion bread and wine are not just symbols but actually become the body and blood of Christ.

This last point was the subject of much debate in the sixteenth century and particularly exercised Martin Luther, who called transubstantiation "a monstrous word for a monstrous idea." In the Thirty-Nine Articles of Religion, adopted under the leadership of Queen Elizabeth in 1563 to spell out the fundamental principles of Anglican doctrine, the belief was ridiculed in the strongest terms:

Transubstantiation (or the change of the substance of Bread and Wine) in the Supper of the Lord, cannot be proved by Holy Writ; but is repugnant to the plain words of Scripture, overthroweth the nature of a Sacrament, and hath given occasion to many superstitions.

In an opinion column for The Times of London on Thursday, Libby Purves pointed out that Anglicans will also have to accept "tough teachings on divorce and the contraceptive ban."

Then again, Anglican converts could also just follow the lead of many Catholics and simply decide to not accept the Church's guidance on a host of social issues. According to a survey by the Pew Forum on Religion and Public Life on the eve of Pope Benedict XVI's visit to the United States in 2008, American Catholics, at least, seem to feel perfectly entitled to not embrace some of the Church's core beliefs.

Pew noted, for instance that "Despite the Catholic Church's strong opposition to abortion, a slim majority (51 percent) of Catholics believe that abortion should be legal in most or all cases." An even larger majority of American Catholics (55 percent) surveyed by Pew supported stem-cell research, despite the Church's opposition, and still more of them (60 percent) said they favored the death penalty, even though the Church opposes it.

What these findings suggest is that, despite the protestations of Catholic officials, there may well be at least as much diversity of belief among Catholics as there is among Anglicans. Given this, it is no wonder that the powerful leader of nearly half of the world's Anglicans, Archbishop Peter Akinola, head of the Church of Nigeria, and the spiritual leader of Africa's 40 million Anglicans, failed to jump at the Pope's offer this week? An aide told The Wall Street Journal that Rev. Akinola is "still weighing the implications of the Vatican's offer."

As Will Connors reported for The Journal from Nigeria on Wednesday, Anglicans in Africa, where homosexuality remains "a cultural taboo," were particularly disturbed by the ordination of the openly gay American Eugene Robinson as a Anglican bishop in 2003. Reverend Akinola's Nigeria's Anglican Church "proffered one of the loudest condemnations of Rev. Robinson's appointment and broke off ties with its American and Canadian counterparts."

Given that, the Pew study of American Catholics might give Anglican conservatives looking for a global community of like-minded coreligionists some reason to look before they leap. In addition to other socially liberal positions, the research found that, in the United States at least, "Catholics are slightly more supportive of gay marriage than is the public as a whole."

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