Since Joseph Ratzinger's writings on Roman Catholic doctrine have been prominent throughout his term as prefect of the Congregation for the Doctrine of the Faith, now that he's Pope Benedict XVI, he's "a known quantity," says Richard Land, president of the Southern Baptist Convention's Ethics and Religious Liberty Commission.

But evangelicals are known to him, too, says Land's denominational cohort, Southern Baptist Theological Seminary president Albert Mohler: "In his previous writings, this new pope has indicated a clear and genuine understanding of what evangelicals believe. As a matter of fact, he may be the most well-informed pope in history, in terms of evangelical conviction and theological commitments. That is not to say that the pope is in any way sympathetic to those convictions. This much is clear—this papacy is likely to be both interesting and challenging."

Mohler says there's an irony in Benedict's election and the way evangelicals should view it. "The conservatism that leads Ratzinger to defend historic Catholic positions on abortion, euthanasia, and a host of other issues go hand-in-hand with his defense of the papacy, magisterial authority, and the evolving body of Catholic doctrine."

It's common these days to articulate it this way: Evangelicals and Catholics are most united on issues of culture and society, and most divided on matters of ecclesiology.

The view is too simplistic, and ignores the point that evangelicals and Catholics are united on social issues because they share common theological convictions. When articulating arguments against abortion or gay marriage in Western society, it's sometimes more helpful to talk in sociological terms than to quote Scripture. But the tie between doctrine has ...