In the past, competing factions have reportedly tried to negotiate compromise candidates to break deadlocks and prevent undesirable candidates from winning in the end, according to Bruter.

NPR: Arcane Process Encourages Papal Horse Trading

The process can easily go to multiple rounds with the same people theoretically getting the same number of votes each time as cardinals play chicken to see who gets dropped first, Bruter says.

NPR: Arcane Process Encourages Papal Horse Trading

Cardinals used to sign their names to ballots, but stopped doing so "due to an old history of intrigues and tensions when people used to fear the most serious reprisals for their choices, " says Michael Bruter, who teaches political science at the London School of Economics.

NPR: Arcane Process Encourages Papal Horse Trading