One of the major problems within the Orthodox Christian world during the last century was the control by the national government of the Church—especially pronounced in the Communist governments of Russia and China—and that issue is addressed in this article from Catholic Culture.
“Speaking at the Ukrainian Catholic University in Lviv, the Vatican’s leading ecumenical official challenged the Eastern Orthodox world to “boldly examine its main ecclesiological problem, namely, autocephaly of national churches and their inclination toward nationalism.”
“From the Orthodox point of view, the Church is present in every local church that celebrates the Eucharist, so each Eucharistic community is a complete church,” said Cardinal Kurt Koch, president of the Pontifical Council for Promoting Christian Unity. “Instead, from the Catholic point of view, a separate Eucharistic community is not a complete church. Therefore, a basis of the Catholic Church is the unity of separate Eucharistic communities with each other and the bishop of Rome. That is, the Catholic Church lives in the mutual intersection of local churches in one universal Church.”