Dear FJ290,
I'm not sure that I can agree with Fr. Auman's or Fr. Z's analysis. Why, then, would the Holy Orders of the Orthodox not have failed, then?
Bishops have the capacity to consecrate a baptized man to be a priest or a bishop. They may not have papal permission or approval, but that isn't required for the ontological change to be effected when bishops consecrate.
We don't hold that a bishop or priest must be worthy, or even orthodox in his theology necessarily for his sacramental actions to be valid.
"With those points in mind, how could any of their clergy be validly ordained?"
Well, the Orthodox don't accept the dogma of the Immaculate Conception, reject the doctrine of Original Sin, and permit divorce and remarriage, and are often a little soft on contraception. Why do we consider their Holy Orders valid?
"For lawful ordination the bishop must be a Catholic, in communion with the Holy See, free from censures, and must observe the laws prescribed for ordination. He cannot lawfully ordain any except his own subjects without authorization."
"Lawful" is licit. There is no question that these consecrations aren't licit.
Validity is a separate question.
What is licit is what is legal. What is valid is what actually occurs. An act may be illicit but valid.
The consecrations of the SSPX bishops were valid, but extremely illicit.
sitetest
This is an explanation from the Catechism, hate to repeat it again, but you asked:
1399 The Eastern churches that are not in full communion with the Catholic Church celebrate the Eucharist with great love. "These Churches, although separated from us, yet possess true sacraments, above all - by apostolic succession - the priesthood and the Eucharist, whereby they are still joined to us in closest intimacy." A certain communion in sacris, and so in the Eucharist, "given suitable circumstances and the approval of Church authority, is not merely possible but is encouraged."
The Eastern churches were with us from the beginning and have much more in common with our doctrines/beliefs than other churches. Indeed, as you pointed out they are soft on divorce and disagree with us on original sin. I'm not too sure about contraception, I will have to do further research that. I will take your word for it. These are issues that indeed put a stumbling block before us for full unity with them. That said, the Orthodox are part of the historic ecclesiastical communities created by the Apostles of Jesus Christ. To say that they aren't, would be to deny our own heritage in Church history.
The Polish National Church circa 1897 and the Old Catholic Church circa 1870 can not make that claim of being present in the time of Apostolic history.