Pope Leo XIV calls for end to wars in Ukraine, Gaza

The balloting process for the papal conclave may be shrouded in secrecy, but it is straightforward.

Each conclave member writes his choice on a paper ballot slip and folds it once in half. He then carries it aloft between two fingers as he walks to the altar.

The slip is then deposited into a special urn used only for the balloting process.

Conclave members are instructed to write their votes “as far as possible in handwriting that cannot be identified as his” to ensure anonymity.

Any conclave member who cannot make it in person to the Sistine Chapel due to illness or infirmity casts his ballot from this room in the Domus Marthae Sanctae. Those ballots are placed in a lockbox and carried to the Sistine Chapel.

Three scrutineers then count the votes by affirming what is written on each ballot and announcing it to the conclave, which allows the cardinals to record the votes themselves.

The first candidate to secure two-thirds of the votes is elected as the next pope.

Read more about the conclave here.

The prospect of an American becoming pope is "very unlikely," according to Dr. Miles Pattenden, a historian of the Catholic Church and a lecturer of history at Oxford University in England.

"There has traditionally been a lot of wariness about a pope from the Anglosphere," Pattenden said. "I shouldn't think that the current circumstances change that, especially now with the tensions between the Vatican and the Trump administration."

An American cardinal, Robert Prevost, has nevertheless started to emerge as a front-runner for the papacy, according to Father James Martin, a papal contributor for ABC.

-ABC News' Bill Hutchinson and Megan Forrester

The master of ceremonies has called "extra omnes" -- ordering all those who are not cardinal electors to exit the Sistine Chapel prior to the start of the conclave.

The door to the Sistine Chapel closed as the cardinals begin the process of choosing the new pope.

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Sistine Chapel doors close as conclave beginsThe master of ceremonies has called "extra omnes" -- ordering all those who are not cardinal electors to exit the Sistine Chapel prior to the start of the conclave.

ABCNews.com

The conclave starting Wednesday is the most diverse in history, with cardinals coming from all over the world to elect the next pope.

The majority of the cardinals are coming from Europe, including 17 electors from Italy, five from Spain and five from France.

There are 16 cardinal electors from North America, including 10 from the United States. Additionally, there are four from Central America, 17 from South America, 18 from Africa, 23 from Asia and four from Oceania.

Argentina, the home country of Pope Francis, has four cardinal electors.