Here is my reply from one of my other blogs to an Anglican who professed difficulty with the issue of Infallibility:
On the issue of infallibility, Jesus told his disciples to listen to the Pharisees even though they were corrupt because they taught from the seat of Moses:
"The scribes and the Pharisees sit on Moses' seat; so practice and observe whatever they tell you, but not what they do; for they preach, but do not practice" (Mt 23:2-3).
They had an infallibility when it came to the Faith and morals. That See was passed down obviously. Moses wasn't alive when God became incarnate. God gave Moses this infallibility in the Old Covenant. Jesus says so Himself. Jesus gave the same office (with it's infallibility) to Peter for the New Covenant.
Sure some of the successors of the See of Peter have been scoundrels, but God granted the holder of that office infallibility in pronouncements of Faith and Morals. They cannot say something false when speaking on faith and morals from the Seat of Peter.
Likewise Caiaphas the highpriest, scoundrel as he was, was granted the gift of prophecy by the Holy Spirit on account of his office. The Bible even testifies that he did it not of his own accord:
" He did not say this of his own accord, but being high priest that year he prophesied that Jesus should die for the nation, and not for the nation only, but to gather into one the children of God who are scattered abroad" (Jn 11: 51-52)
Precedence is clearly shown in the Bible for it.
Now, yes, Orthodoxy does have Apostolic Succession which is why their sacraments are still valid, but they lack the fullness of the Faith. They broke away from the Church set up by Christ and passed on to the Apostles with Peter having primacy and the final authority. All the communities in the Catholic Church looked to the See of Peter before the Orthodox split. Many writings of the Fathers attest to this.
The Catholic Church may not be perfect, and it may have had some rotten popes, but Christ promised that he would be with it until the end of time and that the gates of Hell would not prevail against it. And after close to 2000 years, it is still going strong! Anyone who has doubts about the Catholic Church has to sit back and ponder that fact very seriously. For it is only the Catholic Church that can make this claim. All other churches broke from the Catholic Church and most Protestant churches, as we both know first hand from the Anglican Communion, are imploding within themselves.
Whatever reservations you have about the Catholic Church I encourage you to study them hard and long and see if they can not be resolved. And always know for certain that nothing that the Bible teaches contradicts the Catholic Church, and nothing that the Catholic Church teaches contradicts the Bible!