It has occurred to me that I do not have anything written here on Papal Succession. What is it? Why do we have a Pope?
Certainly, having a Pope is one thing that sets Catholicism apart from other parts of the Christian world.
Papal Succession is the connection between the current Pope and St. Peter, the Apostle to whom Jesus gave the "Keys to the Kingdom".
Although the term "Pope" is not in Scripture (neither is the word "Trinity") the idea of an earthly leader for a Heavenly institution is.
Matthew 16:18 shows Jesus recognizing Simon/Peter's faith and telling him that that is the rock (petra/petros in Greek, kephas or cephas in Aramiac) on which the Church would be built. Jesus then gives Peter the keys to the kingdom.
The giving of the keys is an allusion to the Hebrew Scripture Isaiah 22:22 where we see the king giving the keys of his kingdom to a minister, who is in charge of running the affairs of the kingdom. One who holds the keys is in charge.
Peter was in charge of Jesus' earthly kingdom, the Church.
Since apostolic time, every bishop has been ordained by someone who was ordained by a bishop who ultimately was ordained by an apostle. Popes are chosen from those who are ordained (or who can immediately be ordained) bishops. Therefore Popes are descended from the Apostles.
This is part of what makes us Apostolic, as stated in the Nicene Creed ("I believe in One, Holy, Catholic and Apostolic Church").
There is a question in some circles as to whether the present Pope is valid. Some say there hasn't been a valid Pope since the 1960s or thereabouts.
A major problem with this is that the few living bishops who are considered by these folks as validly ordained are very elderly. They will not live much longer. IF they are in fact the only validly ordained bishops, and a Pope is not soon chosen from among them (which is unlikely, as the past several popes have actually been cardinals and younger than these few pre-Vatican II bishops) before they die, apostolic succession will have ended.
Unless the world ends first, this cannot happen. We are told that the gates of Hell will not prevail against the Church. If the Church should run out of eligible candidates for the Papacy, I think it can be safely said that the gates of Hell have prevailed. One of the four marks of the Church will have been erased.
Why would God allow this to happen?