Election of a New Pope

After the death (or resignation) of a Pope, the governing of the Church falls to the Sacred College of Cardinals, whose main responsibility becomes the election of a new Pope. The Conclave, which consists of about 120 electors, is the gathering of cardinals for the purpose of selecting a new pope.  Only cardinals under the age of 80 can vote.  The Conclave takes place in the strictest isolation so as to avoid the possibility of any external influences or interference.  The cardinals who are able to vote enter the Sistine Chapel and follow a detailed procedure for the casting of secret ballots.  Ballots are cast once during the first day of the Conclave, and then two times a day (at a morning and evening session) until a new pope is elected.  Current church law states that one must be a bishop in order to be chosen as Pope, and current practice is that the College of Cardinals will select one of their own number as the new Pope.
Each vote begins with the preparation and distribution of paper ballots by two masters of ceremonies, who are among a handful of non-cardinals allowed into the chapel at the start of the session. Then the names of nine voting cardinals are chosen at random: three to serve as "scrutineers," or voting judges; three to collect the votes of any sick cardinals who remain in their quarters; and three "revisers" who check the work of the scrutineers. On the top half of the rectangular ballot is printed the Latin phrase "Eligo in Summum Pontificem" ("I elect as the most high pontiff"), and the lower half is blank for the writing of the name of the person chosen.  After all the non-cardinals have left the chapel, the cardinals fill out their ballots secretly, legibly and fold them twice. Meanwhile, any ballots from sick cardinals are collected and brought back to the chapel.  Each cardinal then walks to the altar, holding up his folded ballot so it can be seen, and says aloud: "I call as my witness Christ the Lord who will be my judge, that my vote is given to the one who before God I think should be elected." He places his ballot on a plate, or paten, and then slides it into a receptacle, traditionally a large chalice. 
 When all the ballots have been cast, the first scrutineer shakes the receptacle to mix them. He then transfers the ballots to a new urn, counting them to make sure they correspond to the number of electors.  The ballots are read out. Each of the three scrutineers examines each ballot one-by-one, with the last scrutineer calling out the name on the ballot, so all the cardinals can record the tally. The last scrutineer pierces each ballot with a needle through the word "Eligo" and places it on a thread, so they can be secured.  After the names have been read out, the votes are counted to see if someone has obtained a two-thirds majority needed for election -- or a simple majority if the rules are changed later in the conclave. The revisers then double-check the work of the scrutineers for possible mistakes. At this point, any handwritten notes made by the cardinals during the vote are collected for burning with the ballots. If the first vote of the morning or evening session is inconclusive, a second vote normally follows immediately, and the ballots from both votes are burned together at the end. 
When a pope is elected, the ballots are burned immediately. By tradition, the ballots are burned dry -- or with chemical additives -- to produce white smoke when a pope has been elected; they are burned with damp straw or other chemicals to produce black smoke when no pope has been elected yet.  The most notable change introduced by Pope John Paul II into the voting process was to increase the opportunity of electing a pope by simple majority instead of two-thirds majority, after a series of ballots. The two-thirds majority rule holds in the first phase of the conclave: three days of voting, then a pause of up to one day, followed by seven ballots and a pause, then seven more ballots and a pause, and seven more ballots.  At that point -- about 12 or 13 days into the conclave -- the cardinals can decide to move to a simple majority for papal election and can limit the voting to the top two vote-getters. In earlier conclaves, switching to a simple majority required approval of two-thirds of the cardinals, but now that decision can be made by simple majority, too. 
Once a new Pope has been elected, he chooses a name and receives the obedience of the Cardinals.  The senior Cardinal Deacon announces the name of the new Pope, who then gives his blessing to the people, the city, the Church, and the world.  A new Bishop of Rome and universal Pastor of the Church has been chosen!