Most definitely. And it certainly is not "public opinion" polls. I am thinking in particular the heresy of Arianism. St. Jerome once said "the world woke up one day to find itself Arian", when describing the speed in which many people in the Church turned to this heresy. It was only particular orthodox saints of the day guided by God, St. Athanasius corresponding with the Bishop of Rome before and after Nicea, especially, that the Church maintained its orthodoxy. Public opinion polls would have led us to regard Jesus as a different essence then the Father.
By the way, it is noteworthy that both Greeks and Latins consider the Confessor a major saintly figure in our respective communities who upheld the Holy Tradition of the Apostles in the face of heretics - who sometimes were political powers. I believe that St. Leo would be another.
something protects the Church. And it ain't any fallible or brainy men.
One only needs to look at the Medieval popes for proof of that. No doubt something supernatural was guiding these otherwise very poor quality men to continue in the teachings of the Church unadultered.
Regards
There are several pre-Schism popes who are saints in the Orthodox Church, and Leo I is certainly one of them, even though it was the East that challeneged his jurisdictional desires.
One only needs to look at the Medieval popes for proof of that
Beyond that, the oustanding example is also Pope Alexander VI, personally nothing you would consider "fatherly" in a spiritual sense, but he maintained strict Catholic orthodoxy.