Last Thursday, Catholics observed the Feast of the Immaculate Conception. The doctrine of the IC, as set forth by Pope Pius IX in 1854, holds that the Blessed Virgin Mary "in the first instance of her conception, by a singular privilege and grace granted by God, in view of the merits of Jesus Christ, the Saviour of the human race, was preserved exempt from all stain of original sin." To mark the day, Pontifications posted an interesting excerpt from Balthasar, which traces the convoluted and fractious history of the IC doctrine, from the Church Fathers to its elevation to infallibility in 1854. According to Balthasar, the central issue at stake is this: "If Mary is to be the true Mother of the Redeemer, she must genuinely belong to the race of Adam, which stands in need of redemption; at the same time, if she is to be his Mother, she needs to be entirely holy, 'immaculate'." As Balthasar indicates, there has never been real agreement on how to solve this apparent dilemma, and he attributes this to the fact that Mary does not "seem to be really at home" in any theology. Thus, it perhaps isn't surprising that the three branches of Christianity - Orthodox, Protestants, and Catholics - have adopted such radically different attitudes towards Mary.
Pontifications has since posted a lengthy quote from Newman, in which he expresses surprise that "so many learned and devout men stumble at this doctrine [of the Immaculate Conception]." Frankly, I'm surprised that he was so surprised. The IC doctrine causes such great offense among Protestants, not because we have a low opinion of Mary, but because so many of the worst characteristics of Catholic theology are evident in this doctrine. It is the product of rampant theological speculation completely unhinged from Scripture (the cited proof texts, Genesis 3:15 and Luke 1:28, are laughably weak) with its truth simply asserted by papal fiat, and it reveals an obsession with Mary that is tough for Christocentric Protestants to swallow. Moreover, as Balthasar's quote makes quite clear, there has never been a real consensus concerning nature of Mary's conception (in other words, the IC is clearly not something that has been believed by Christians at all times and in all places). Thus, it was somewhat presumptuous of the Catholic Church to raise the IC to the level of infallible doctrine, thereby creating a huge obstacle to future unity with Protestant and Orthodox Christians.
If nothing else, the doctrine of the IC should serve as a reminder to Protestants that several ecumenical barriers have been erected by Catholics since the Reformation, including the doctrine of papal infallibility. This fact is often forgotten by evangelical catholics who point to the (limited) agreement on justification as evidence that the Reformation divisions need no longer apply, as the central issue has been dealt with. Yet, in my estimation, the doctrines of papal infallibility and the IC (as well as the issue of Mary in general) are just as divisive.