The Episcopal Church was formed after the American Revolution as an ongoing expression of Anglicanism in the United States. In recent decades, however, the Episcopal Church has progressively taken on a revised view of Anglicanism and of the Apostolic Faith, what is known as Modernism and Modernist Theology. The Episcopal Church today, particularly among many of its clergy, understands the Faith in some ways inconsistently with the Faith of the Apostles as recorded in Scripture and the Faith of much of the Anglican Communion throughout the world.
Two salient issues differentiating Apostolic Christianity (classic Anglicanism) from Modernism (The Episcopal Church) are the authority of Scripture and the uniqueness Christ. This is far too limited a venue to fully explain, but in modernist thought the revelation of God in Scripture in many of its facets is seen as outdated and overridden by modern experience and human intellect. Similarly, the uniqueness of what God has done in Christ has given way to an openness and inclusivity that trumps the apostolic understanding and eyewitness experience of the person and work of Jesus.
This theological drift in the Episcopal Church and all its ramifications has caused a fragmentation in the Anglican Communion. Presently the Episcopal Church finds itself in what has been termed “impaired communion” with much of the Anglican Communion. North American Anglicans who could not go where the Episcopal Church is theologically headed and who wanted to stay with the broader Anglican Communion appealed to other provinces of the Anglican Communion to take them under their wing, at least in some interim fashion. This congregation, The Church of the Holy Trinity, is a good example. Holy Trinity was a church plant under the authority of the archbishop of Nigeria. The foreign archbishops subsequently have encouraged the formation of a new Anglican province under which orthodox Anglicanism could re-gather in North America. The Anglican Church in North America thus came into being. An Archbishop of this new province was consecrated, and dioceses have formed.
We thus have two expressions of Anglicanism in North America, one modernist, the other traditionally orthodox. We should note that there are many orthodox believers still in the Episcopal Church, particularly among the laity. There are also whole dioceses still in The Episcopal Church that are orthodox, such as the Diocese of SC (lower part of the state). But the Episcopal Church leadership and clergy have a strategy to redefine Episcopalianism. That process is essentially complete.