Only as long as it is found to be so using the Act 17:11 and Mark 7:6-12 rule of sola scriptura testing.
As Paul warned us -
Acts 20:28 Be on guard for yourselves and for all the flock, among which the Holy Spirit has made you overseers, to shepherd the church of God which He purchased with His own blood. 29 I know that after my departure savage wolves will come in among you, not sparing the flock; 30 and from among your own selves men will arise, speaking perverse things, to draw away the disciples after them. 31 Therefore be on the alert, NASB 1955
28 Keep watch over yourselves and all the flock of which the Holy Spirit has made you overseers. Be shepherds of the church of God, which he bought with his own blood. 29 I know that after I leave, savage wolves will come in among you and will not spare the flock. 30 Even from your own number men will arise and distort the truth in order to draw away disciples after them. 31 So be on your guard! Remember that for three years I never stopped warning each of you night and day with tears. NIV
Note that in this document, I shall be referring to the Book of Revelation, properly titled the Apocalypse of St. John and commonly known as Revelations in the vernacular, as the Apocalypse, as I feel it is more accurate since the book is the only canonical Apocalypse in the New Testament.
We can identify the savage wolves St. Paul warns us of as the heresiarchs like Marcion, who tried to distort the apostolic testimony of St. Paul to falsely claim that the Holy Apostle taught Marcion’s doctrine, that the LORD of the Old Testament was different from the God of the New Testament, and in opposition to Him, when in fact they are the same deity, as is proven by the Christological prophecy in the Old Testament, and Valentinus, Tatian, Severian, Montanus, Sabellius and other second century heresiarchs with their own doctrine. There was an explosion of heresy after the martyrdom of St. Paul in fact; before he was executed in Rome the only heresies we know of was that taught by Simon Magus, as well as some adherents of St. John the Baptist who did not accept our Lord, but after St. Paul we get Cerinthus, Basilides, Marcion, the Ebionites, and others, a veritable litany of heretics which St. John warns us about in his epistles, which are believed to postdate the Pauline epistles.
Furthermore, we are assured by Matthew 16:18 that the Gates of Hell will not prevail against the Christian Church, and they did not (this I personally believe is a scriptural oversight in Restorationism, whether we are talking about Quakers, some Baptist movements, the Stone-Campbell Movement, the short-lived 19th century Catholic Apostolic Church, or any other church which has a doctrine that it represents a restoration of the Apostolic Church).*
The Restorationist principle further collapses when we recall the Church at the Councils of Nicaea and Constantinople defined the Nicene Creed, which is the bulk of the Christian Forums Statement of Faith (along with a few addendums to deal with problems not faced by the Nicene Church, such as a prohibition on the denial of the apostolate of St. Paul, because apparently some wackos joined the site and tried to teach that, and other strange doctrines; the Christian Forums Statement of Faith would make an ideal ecumenical Statement of Faith, actually, as it is broadly inclusive of Nicene Christians while excluding the various cults that now exist, which is what St. Paul was actually warning us about. The SDA also affirms that their beliefs align with this creed.
We can further identify the the Nicene Church as legitimate because it propagated, in the 5th century, with the help of St. Augustine and the Roman pontiff Gelasius, the 27 book Athanasian Creed which all Christian churches agree on. And we know for a fact that before St. Athanasius, no one else, not Eusebius, not Origen, not St. Irenaeus, not St. Jerome, and not the compilers of the Syriac Peshitta, whose views were broadly consistent with the Catechetical School of Antioch, had agreed on the precise 27 books St. Athanasius enumerated as protocanon. They either omitted books, or gradated the canon, with the Apocalypse (Revelation) lumped in with the Shepherd of Hermas and 1 Barnabas, or deleted the it along with 2 Peter, 2 John, 3 John, Jude, and in several cases Hebrews, Timothy, Titus and Philemon, as all of those books were of disputed authenticity, before St. Athanasius declared them canonical in the Church of Alexandria (which at the time included all of Egypt (with the possible exception of Sinai, now an autonomous part of the Church of Jerusalem), the Sudan and Ethiopia, and possibly Libya or portions thereof). Once he had done that, this list found favor in the Roman Church, which according to your own Ellen G White in
The Great Controversy was not yet under illegitimate control, and the Roman and Alexandrian churches prevailed over the Antioch-educated Patriarch of Constantinople, Nestorius, at the Council of Ephesus in 433, and most of the Catechetical School of Antioch which fought against the inclusion of the Apocalypse, which is central to Adventist doctrine, was banished to Nisibis.
So, because of this, we can assert the Church at the time of the Council of Ephesus at least was completely dogmatically Orthodox, and not what St. Paul was warning us about.
* Even if one is committed to Restorationist doctrine, which is to say the ifea that the Great Apostasy is not a prophecy of future or present events (which seems to me more likely given the decline in Christianity and the increase in persecution of Christians in historically Christian lands, starting with Canada, but now extending to the UK, Canada, and various EU countries, where the free expression of scriptural doctrine concerning homosexuality is being muzzled and American evangelists of a conservative theological orientation are being denied entry), the problem becomes, when did the Great Apostasy happen? The problem is that if you say it happened immediately after the death of St. Paul, that’s a problem because the Apocalypse was written long after the martyrdom of St. Paul, with the traditional date of composition being sometime between 75 and 90 AD,** and if you date it to the repose of St. John the Apostle, traditionally dated to the final decade of the first century, which seems that much more plausible given the reasonable presupposition that he was a teenager during his discipleship of Jesus Christ (which would explain the special love our Lord had for him, as for all children, possible youthful immaturity on his part and the part of his older brother St. James the Great, who would likely have been in his early 20s in this scenario, and our Lord entrusting him to the matrimony of his own mother from the Cross), or the conversion of St. Constantine, these ideas run into an equally severe problem, that being that the Nicene Creed, which defined what it means to be a Christian, was defined at the Council of Nicaea, convened by St. Constantine, and the Council of Constantinople, convened by St. Theodosius (with the Roman church adhering but not actively participating in these councils, sending only a few legates and no bishops) and the canon of St. Athanasius, which was the first to definitively pronounce the Apocalypse as canonical, was written in the fourth century, and was universally accepted in the fifth.
This is not a problem for Protestant churches as a whole, because it was obvious even to Roman Catholics that the Roman church under Pope Leo X, and especially Pope Alexander VI, of the infamous Borgias, required Reformation, hence the Counter Reformation which abandoned the sale of indulgences and introduced seminaries, so only qualified men could be ordained to the priesthood (I still believe that a discerning bishop or senior presbyter should have the prerogative of ordination, and several churches including ROCOR, the Assyrian Church of the East, and the Coptic Orthodox Church, as well as some Protestant churches, do not require seminary education, but in the Roman church it may have been a needed reform as you had the Borgias and others appointing young teenagers to the episcopate, and also there was a problem with illicit simony; the Roman Church also does not subscribe to the ancient canon followed in the East which sets the minimum age for a presbyter to 30). So, the churches of the Protestant Reformation actually helped the Roman Church, by forcing the much needed reforms of the Counter Reformation.
From an ecumenical perspective, we can arguably date the problems with the Roman church to the schism with the Eastern churches, and indeed two of the earliest Protestants, St. Jan Hus and St. Jerome of Prague, were glorified as martyrs by the Czech-Slovak Orthodox Church because of their work to restore Orthodox practices such as a Slavic-language liturgy and communion in both kinds, which had been offered before Austria conquered what we now call the Czech Republic. Additionally, the Lutherans believed their reforms were in accord with the doctrines of the Greek church and it was a disappointment that the dialogue between Lutheran theologians and Patriarch Jeremias II was unsuccessful.
Restorationism confuses the issue, by assuming that a Great Apostasy that was somehow either the fault of collusion between the Roman Church and Emperor Constantine, despite the fact that Constantine had a much closer relationship with the Church of Constantinople, which he set up, and the Roman Church barely participated in Nicaea other than to send non-voting legates in support of St. Alexander of Alexandria and his successor as Patriarch, St. Athanasius, against Arius, and the Council of Constantinople likewise revised the creed to exclude more doctrines that we would agree today constitute a departure from Christianity, such as Macedonianism, the belief that the Holy Spirit is not a divine person. And it was St. Athanasius, who procured the removal of Arius, whose doctrines were rejec5ed by Ellen G. White, also defined the Athanasian Canon.
So from a Restorationist perspective, the best course of action for the SDA is to define the Great Apostasy as occurring in 538, or being confined to the Western church or parts of the church other than Alexandria and the persons of St. Athanasius, because Ellen White’s doctrine depends on the pro-Trinitarian outcome of the Council of Nicaea, and the adoption of canon of St. Athanasius by the entire Christian Church in the fifth century.
I personally prefer the approach of the Christian Church/Disciples of Christ, the direct descendant of the Stone-Campbell movement, which has become a mainline Protestant church in ecumenical relations with other mainline churches which are not Restorationist, open to dialogue, using the Revised Common Lectionary and being a part of liturgical Christianity, while retaining a nominally Restorationist heritage mainly in the form of credo-Baptism.
** some dubious scholars of the sort one might find at the Harvard Divinity School, which is almost as overrated as the Harvard Business School*** dating it to the second century, but I reject their opinion.
*** The Harvard Business School is disproportionately represented among the ranks of CEOs of American companies whose management practices and compensation could be considered controversial, and among the ranks of McKinsey & Co., the most prestigious (in every sense of the word) management consultancy, whose past clients include a disportioncate number of businesses which were liquidated or went through Chapter 11 reorganization.
