Like so many other such issues, the one I have in mind is ecclesiological: just what does being "in communion" with the Catholic Church consist in? What are the necessary and sufficient conditions? How and when are they met? And how, short of juridical excommunication, does a Catholic get herself out of communion with the Church? I once thought that debating such questions was just an arcane theological exercise, the sort that occupies people who don't have to worry about mere temporalities such as earning a living or changing diapers. But in fact it is anything but. The questions that arise here affect us all on the personal, pastoral, and political levels, which are intertwined in many ways. The issue is also very much an apologetical one. Since I can't do everything in one post, I shall focus on the issue mainly from that angle.
One thing that I've consistently observed since Vatican II is that many people, Catholics as much as non-Catholics, have the impression the Church's teaching on membership in the Church is, or rather has become, incoherent. It is widely believed that the Church once taught that you had to be what we'd now call a "card-carrying Catholic" to be saved—and even for those people, the prospects were pretty dicey. Being such a Catholic entailed being "in communion with" the Church of Rome. But having been exposed to Vatican II and ecumenism, many people now believe that the Church no longer teaches that. The general impression seems to be that the Church now teaches that you can squeak into heaven, perhaps by way of purgatory, just by avoiding the grossest and blackest forms of wickedness and being vaguely contrite, in the end, about one's preferred forms of wickedness—or at least about those which one has managed to recognize as such. From this point of view it hardly matters what religion you profess, or even whether you profess any at all.
Of course the above is a caricature I've devised for expository clarity. But it is not a terribly unfair caricature of how many people see these things. It is actually a reasonable summation of what I've been hearing for decades. And how such people see these things is not only wrong but terribly unfair to the Catholic Church, whose teaching on this subject is profound, nuanced, and still developing. Explaining why will help illustrate what being "in communion" with, and thus a member of, the Church actually means—and why that is important.
It is true that the Catholic Church has taught, with her full authority, the doctrine extra ecclesiam nulla salus: "outside the Church, there is no salvation" ('EENS' for short). For people who care about such facts, I don't even need to document that. It is also true that Vatican II did not repeat the words of EENS, at least as a pastoral matter. For what the Council did say, I always urge people to read the documents, especially Lumen Gentium and Unitatis Redintegratio. But for now, here are the three most pertinent statements (emphases added):
Basing itself upon Sacred Scripture and Tradition, [this sacred Council] teaches that the Church, now sojourning on earth as an exile, is necessary for salvation (LG §13).
Even in the beginnings of this one and only Church of God there arose certain rifts,(19) which the Apostle strongly condemned.(20) But in subsequent centuries much more serious dissensions made their appearance and quite large communities came to be separated from full communion with the Catholic Church-for which, often enough, men of both sides were to blame. The children who are born into these Communities and who grow up believing in Christ cannot be accused of the sin involved in the separation, and the Catholic Church embraces upon them as brothers, with respect and affection. For men who believe in Christ and have been truly baptized are in communion with the Catholic Church even though this communion is imperfect (UR §3).
Those also can attain to salvation who through no fault of their own do not know the Gospel of Christ or His Church, yet sincerely seek God and moved by grace strive by their deeds to do His will as it is known to them through the dictates of conscience (LG §16).
The key development of doctrine here is this: those who are, for whatever reason, not culpable for failing to become formally members of the Catholic Church, can still be saved by responding positively to that grace, won by and coming from Christ, which is given to humanity in and through the Church, i.e. the Catholic Church. (The Catechism of the Catholic Church's explanation of EENS helps to make that clear.) The people so described are thus in "imperfect" communion with the Church. Being "in communion with" the Catholic Church thus is, or often can be, a matter of degree—just as the journey of the "pilgrim Church" herself toward eschatological fullness is a matter of degree. And if you are objectively inculpable for that degree's not being full, then you're "in," at least to a degree that can enable your salvation.
That matters a lot for ordinary pastoral practice, evangelization, and missionary activity—for only God can really know who is culpable and who isn't. But the idea of imperfect communion remains very controversial in some quarters, probably because it is so widely misunderstood.
It is often taken to mean that EENS has been, at least from the standpoint of logic, repudiated by the Catholic Magisterium. Of course I have vigorously argued that EENS has not been thus repudiated. My first formal argument to that effect was made in a 2006 post at the now-defunct version of Pontifications, where it evoked a combox running to well over 300 entries, many of which were scholarly. That post is preserved as the first dogma-specific entry in my long essay Development and Negation. The point the naysayers couldn't (or, in some cases, wouldn't) see was itself simple: it is one thing to say that there's no salvation outside the Church; it's another to say what being inside the Church can consist in. The former claim remains the teaching of the Church, now expressed by LG's formulation that she is "necessary for salvation." But the latter claim is that being in the Church, or at least being related to her in a salvific way, is often a matter of degree. That is a real development of insight into the fixed content of the deposit of faith.
What most interests me at the moment, however, is not how non-Catholics can be in some degree of communion with the Church, but how Catholics themselves can fail to in full communion—and why that matters.
The Eucharist is, among many other things, an expression of the intimate unity between God and his people, between Christ and the Church. As such and perforce, it is also an expression of the full unity of faith and graced fellowship among those who share it. So even American Catholics are taught, rightly and in considerable detail, that if they have sinned seriously in this-or-that way, they would be profaning the Eucharist by receiving it. That is because it is held, on the basis of Scripture and Tradition, that those who have abandoned their baptismal vocation by falling into mortal sin are no longer in full communion with the Church, and thus would be lying to the Church, and well as dishonoring the Body and Blood of the Lord, by receiving it into their bodies. Those who receive "unworthily" thus receive "unto their own condemnation" (cf. 1 Cor 11: 23-30). If they are thus and culpably not in full communion with the Church, they can be saved only if they repent. So much used to be taken for granted by Catholics in general, and still is in some quarters. Most Catholics know that, if they have committed sins such as adultery or grand larceny, they need to do something to reconcile with God and the Church.
Now even Catholics who only formally cooperate with grave and intrinsic evils, such as abortion, are committing what is, objectively speaking, serious sin. Hence and in particular, Catholic politicians who support laws giving wide scope to the practice of abortion are doing grave wrong. But it does not necessarily follow that they are guilty of that sin, so that they profane the Eucharist if and when they receive it. That follows only when (a) they are aware of how the teaching of the Church applies in this case, or (b) if they are unaware, they are culpable for being unaware. And the same holds for Catholics in general about any sort of serious sin, especially that of heresy. This is where the problem of pro-abort Catholic pols really arises from.
On a whole host of issues, mainly those having to do with sexuality, marriage, and procreation, many American Catholics do not actually believe the definitive teaching of the Church. And so, of course, they feel no obligation to live by it. The Catholic politicians they help elect are, by and large, no exception. The practical question which thus arises for the Church's pastors, especially the bishops, is whether such people should be presumed culpable for that or not, and thus whether they should be denied the Eucharist or not. In most cases, bishops and priests presume that people are not culpable for their infidelity to Church teaching. They presume either that people are approaching the Eucharist in good conscience or that it is not the role of pastors to judge the consciences of communicants when they march up to receive. And in the case of many ordinary Catholics, that presumption is correct. The depth of ignorance and deception among ordinary Catholics, which reached new lows in the decade or so after Vatican II, remains so great in many instances that such Catholics cannot be presumed culpable when, out of habit and sentiment, they receive the Eucharist. And so, even when such a Catholic is objectively culpable for not being in full communion with the Church, the appearance of full communion on their part is generally kept up.
Nevertheless, that poses a serious obstacle to evangelizing both ignorant Catholics and the culture at large. If, for what seem to be sound pastoral reasons, many Catholics who neither believe nor live by the moral teaching of the Church are receiving the Eucharist with apparent impunity, then how seriously are ordinary Catholics and the world at large to take such teaching? The general impression has become that such teaching is optional: a rather dismal section of the cafeteria line that one is free to bypass and that will, sooner or later, be tossed along with all the other food nobody buys. Thus the policy of keeping up appearances for the sake of pastoral economy has the effect of entrenching, on a wide scale, the very problem that occasioned the policy in the first place. And so, the preaching of the full Gospel has been largely buried under a collective rationalization. That, I am convinced, is the basis of most of the other problems in the American Catholic Church, including the sex-abuse-and-coverup scandal that peaked five years ago. I blame the bishops for the fundamental problem as much as for its most egregious manifestation.
It can be argued that, given the sorry lack of adult catechesis, there is no practical alternative to the present policy of keeping up the appearance of full communion in the case of Catholics who are objectively not in full communion. That's what many bishops do argue, and the argument is cogent. One cannot just pick out, and pick on, the ordinary Catholics who are implicated in this mess. Most of them are not morally responsible for it, nor is it their role to clean it up. But one can and ought to pick out and pick on erring Catholics who have the education to know better and the power to affect a great many lives by their actions. I mean, of course, the Nancy Pelosis and the Joe Bidens. Archbishop Chaput has had some especially trenchant things to say about such people. If they have excuses, they shouldn't be left with them. Too much is at stake.
But there is a still-more fundamental problem here. Having acknowledged and taken into account the reality of imperfect communion for many non-Catholics, Rome must do the same for many Catholics, if only for self-consistency's sake. If she does so, as she has done for decades, she only reinforces the Church's internal problem for the reason I've already stated. If she does not, she becomes pastorally inconsistent: ecumenism will apply only to those who were never formally Catholic, so that we'll end up with a much smaller, if purer, Church. The Pope seems headed, slowly, in the latter direction. How he and his successors will carry on with it remains, however, an open question. In the meantime, the American bishops continue to disagree about how to handle the Pelosis and the Bidens. Maybe that's inevitable.
Either way, they should be more concerned with the formation of ordinary Catholic adults. Almost a decade ago, the USCCB produced a bracing document which points the way. Little has been done to implement it. I'm waiting with my resumé in hand.