How has apostolic succession been "unbroken" in the wake of depositions, antipopes, immorality, and simony?

Question

In studying the history of the papacy one discovers all sorts of events that are interesting when considered in the context of apostolic succession from St. Peter until today, including, but not limited to:

• Instances of popes being involuntarily deposed by conquering sovereigns and replaced with one sympathetic to that conqueror.
• Instances of contention over the papacy by two or even three popes simultaneously, accompanied by multiple colleges of cardinals and bishoprics.
• Instances of nepotism and dynastic possession of the papacy by aristocracy and politicians.
• Instances of popes engaging in orgies, conspiracies, accepting bribes, fathering children, and even committing murder.
• Instances of the papal office being sold.

Is the nature of apostolic succession meant to be an unbroken succession of valid popes? How does the Catholic Church address these events and the manner of succession when making the claim (from New Advent):

The fact is indisputable: the Bishops of Rome took over Peter's Chair and Peter's office of continuing the work of Christ. To be in continuity with the Church founded by Christ affiliation to the See of Peter is necessary, for, as a matter of history, there is no other Church linked to any other Apostle by an unbroken chain of successors.

Answer 1

Apostolic succession and Papal succession are not one and the same.

Is the nature of apostolic succession meant to be an unbroken succession of valid popes?

No. Rather the nature of apostolic succession is meant to be an unbroken succession of valid bishops.

Not just the pope, but all Catholic bishops have unbroken apostolic succession. In other words, for a person to become a bishop (even the bishop of Rome - aka pope), he has to be consecrated (Laying on of hands) by another a validly consecrated bishop. Who in turn should have been validly consecrated by another validly consecrated bishop...... If we keep backtracking like this, we will end up with one of the thirteen apostles (The Twelve + Paul). This is considered to be unbroken line of apostolic succession.

Popes might validly succeed each other if and only if they have proper apostolic succession (i.e they are validly consecrated bishops). This is why Stephen II is not considered a pope.

The quote you have mentioned talks about continuity in the see of peter. That is the continuity in papal succession. In other words, there is no time in history of papacy where the see of peter (or the post of the pope) is deserted with no claimants and no conclave was held to elect his successor. Note that the see could be vacant, but during that time the conclave could be taking place. This is what is called unbroken line of successors of Peter.

Instances of popes being involuntarily deposed

New popes are not considered valid unless the previous pope submits to his authority. (As in deposing of Pope John XII and Pope Leo VIII's invalid first election)

Instances of contention over the papacy by two or even three popes simultaneously

Even though at the time when this was happening, it was unclear as to who is the legitimate successor, we can be sure that at least one of them was legitimate. In other words, the see of peter was not vacant. (Retrospectively we can determine the legitimate successor.)

Instances of nepotism and dynastic possession ... popes engaging in orgies, conspiracies, accepting bribes ....

Sinfulness of the person holding the office does not invalidate the office itself.

Instances of the papal office being sold.

If a reigning pope resigns for money, it is a sin (Simony). Like all sins this is also a voluntary act. Hence he will cease to be pope.

Answer 2

Instances of popes being involuntarily deposed by conquering sovereigns and replaced with one sympathetic to that conqueror.

A specific example is need to answer this question. See below.

Instances of contention over the papacy by two or even three popes simultaneously, accompanied by multiple colleges of cardinals and bishoprics.

Ah, the Great Schism. At the time, due to practical politics, the stituation was very confusing (I want to be loyal to this Holy Father, but the King is going in a different direction). However, in retrospect, the situation is easily understood, once the confusing cloud of Medieval politics fades.

Instances of nepotism and dynastic possession of the papacy by aristocracy and politicians.

Instances of popes engaging in orgies, conspiracies, accepting bribes, fathering children, and even committing murder.

A Bishop is per se a man who has received the fullness of Holy Orders. What his actions are are irrelevant to the definition of a Bishop. The Pope can do outrageous things, but that doesn't effect the validity of his office, for it was founded by Christ Himself (I'm sure you know the Matthew quote ;-) ). The personal Holiness of a Bishop is per accidens in regard to his Office, just as the languages he speaks and his race are "coincidences." To put it simply, Holiness of the Office does not necessarily relate to Holiness of the person in the Office.

However, those with Holy Orders do have access to special Graces, although many (as you can see) have rejected them. But look at what happens when they do accept them!

Instances of the papal office being sold.

A specific example is need to answer this question.

there is no other Church linked to any other Apostle by an unbroken chain of successors.

This is false. The Pope of Alexandria, for example, still possesses valid Holy Orders, and can trace them straight back to St. Mark. All the Eastern Churches have Succession as well. The Indian Christians were never techniquely out of communion with Rome (although they we're out of communication for 1000 years), and their Orders seem to trace back to St. Thomas.

The Bishops do not necessarily need the Pope of Rome to transmit a valid Holy Orders (otherwise he would have to be present at all Ordinations). It is considered "illegal" if done in a church outside of the Catholic communion, but it is still valid nevertheless. The Church isn't a monarchy, with the Pope as King; it's more like a federal system, with the local Bishop at the bottom, taking care of his flock, archbishops next, Patriarchs, and finally the Pope of Rome, the successor of St. Peter. The idea is not that the Pope will micromanage everything, he already has too much to do in Rome anyway. The local Bishop is suppose to work together with his priests for those people in their jurisdiction, and if a conflict outside his area arises, he can appeal to a higher authority for assistance, or the higher authority, seeing the need to intervene against the local bishop, can do so. Remember, this is the ideal; due to original sin, reality doesn't always work this way, sadly. In a sense, all bishops are ultimately equal (and powerless individually; only the College, and then, only the College in relation to the Church, is protected from error. Only the Bishops as a whole have authority), but the Roman Bishop, being the head of the College of Bishops, has certain powers necessary to resolve conflict within the College itself, otherwise the College will collapse on itself. The fact that Christ foresaw the need for all this is evidence for His Divinity, IMHO.

The Bishops are Successors of the Apostles. In fact, they are Apostles. All those powers and responsibilities that Christ gave to St. Peter, St. James, St. John, etc., like the power to "bind and loose" and the responsibility to "feed My sheep" have been passed down, handed down, to the Bishops in an unbroken Tradition. The Father sends the Son, the Son sends the Apostles, and the Apostles send their successors, and those successors send their successors, all the way down to Bishops like Pope Francis today, who will send their successors to the next generation, until the return of our Lord.

Just from a secular point of view, the fact that the Bishop of Rome's line can be traced down to the first century AD is just astounding, to say the least.

Christi pax.

Answer 3

Here's what the First Vatican Council says regarding the perpetuity of the Petrine office (ch. 2 "On the Perpetuity of the Primacy of blessed Peter in the Roman Pontiffs"):

That which the Prince of Shepherds and great Shepherd of the sheep, Jesus Christ our Lord, established in the person of the blessed Apostle Peter to secure the perpetual welfare and lasting good of the Church, must, by the same institution, necessarily remain unceasingly in the Church; which, being founded upon the Rock, will stand firm to the end of the world.

Notice, it did not say: "There will be an occupant of the chair of Peter at all times." Perpetuity refers to the institution of the Papacy, not the holders of the office. Otherwise, even interregnums (i.e., the period of time between the death of a Pope and the election of his successor) would "break" the Apostolic succession.

It's also entirely possible and in-line with Catholic theology that Pope Pius XII was the last valid Pope, as sedevacantists* today believe. Even if the world ended today, this would not mean the Petrine office ceased at the death of Pope Pius XII in 1958. And nothing in Catholic theology says interregnums cannot be 57+ years.

^{*(from the Latin: "sede vacante" meaning "vacant chair")}