Nothing fuzzy about it. Those who confess the essentials embodied in the Nicene Creed are orthodox (little o) Christians and will be saved to the extent that their faith is genuine. Those who deny these doctrines have "another Jesus."
I, too, am sympathetic to the idea that "if you can recite the Nicene Creed and mean it, you're probably okay". Is the Creed really a sufficient sine qua non
of Christianity, though?
"I believe in one God" -- Mormonism, which clearly confesses more than one deity, is excluded, as is Christadelphianism.
"maker of all things" -- anyone denying creation ex nihilo
"And in one Lord, Jesus Christ" -- Nestorianising-type protestantism, which has a tendency to hold the divine and human natures apart, is excluded.
"of one essence with the Father" -- Arianising-type protestantism, which has a tendency to talk lots and lots about "Jesus" but never "Christ our true God" is excluded.
"and was incarnate of the Holy Spirit and of the virgin Mary" -- Nestorianising-type protestantism, which refuses to confess that the ever-virgin on is Theotokos, is excluded.
"and became human", "and suffered and was buried" -- protestantism of docetist or adoptionist tendencies, which denies the hypostatic union, is excluded.
"will come again in glory to judge the living and the dead" -- those confessing an "already happened" eschatology are excluded.
"whose kingdom shall have no end" -- chiliast protestantism and other forms confessing a heretical eschatology are excluded.
"who proceeds from the Father" -- the Roman Church is arguably excluded, as is every other Western confession.
"who together with the Father and Son is worshipped" -- Christadelphianism, at least, is excluded, as would be protestantism of Macedonianising-type pneumatology.
"one, holy, catholic and apostolic church" -- not even going to comment on this one, lest we all be bored to death by the essay which would follow.
"one baptism" -- anabaptist confessions are excluded.
"for the remission of sins" -- anyone confessing that baptism is just a symbol of an already-accomplished reality is excluded, ditto the Eucharist.
"I expect the resurrection of the dead" -- anyone expecting a fuzzy, wishy washy spiritual resurrection is excluded.
The whole creed taken together -- oneness pentacostalism and like heresies which do not confess the Most Holy Trinity in the orthodox manner are excluded.
This list has certainly not caught every inchoate and nebulous heresy which abounds in the Christian world, but I trust it is illustrative.
Please do not go to the effort of proving to me that some of these confessions do not really believe as I have described. The point I am making does not hang on whether I have correctly defined the theology of particular groups (you will note I have largely refrained from attempting to).
I've seen too much good in Protestantism, too many people in my life who just seem to ooze the love of God. Orthodoxy seems to require me to see them as the exception, the "incomplete" who will saved by the skin of their teeth. What's more, a practicing atheist or hindu would be saved in the same way, implying there is no essential difference, and to that makes a mockery of the Scriptures. I just can't accept that. I've seen and heard of too many small, faithful congregations, simple people who care for their own and put my own faith to shame a thousand times over.
As a Protestant I can accept the grace of God in these places and just as happily when it is found in Orthodoxy. If I were Orthodox, it would all be an anomaly. My default position toward a heterodox Christian would have to be, "lost until proven otherwise."
Again, I sympathise very much with this. I would simply reiterate that of those more has been given, more is expected. The converse is probably also true.
I know a reductio ad absurdum can be made here regarding the Mormons and other Christian-like cults, but I hope I've given my reasons for not accepting that comparison.
Thank you for sparing me the effort, haha. Seriously, though, please do meditate further on that reductio
, as it is instructive.