Pope Benedict announced today he had changed the rules to elect his successor in a move meant to ensure that future pontiffs have two-thirds support from the conclave.
Pope Benedict's motu proprio, a type of papal decree, partly reverses changes made by his predecessor John Paul II that had opened the possibility of electing a Pope with only a slight majority in the event of a deadlock.
From now on, the two-thirds majority needed at the start of voting in the conclave will be required until the very end - no matter how many rounds of balloting end with "black smoke" from the Sistine Chapel above St. Peter's Square.
The Vatican's chief spokesman, Fr Federico Lombardi, said the changes "would guarantee the widest possible consensus for the election of the new Pope."
Pope Benedict (80), in a bid to address the deadlock issue, calls in his decree for a run-off vote between the top two candidates after 33 rounds of voting.
No such extremes were needed in 2005, when then-Cardinal Joseph Ratzinger was elected on just the second day of the conclave.
He had at least a two-thirds majority, but what happened behind closed doors in the frescoed Sistine Chapel in April 2005 is secret.
But one account published in a respected Italian magazine in 2005 said Cardinal Ratzinger was elected Pope only after his closest rival in the conclave, Cardinal Jorge Mario Bergoglio from Argentina, indicated he did not want the responsibility.
In the fourth and final round of voting, Cardinal
Ratzinger was elevated to the papacy with 84 votes - less than the 99 votes thought to have been cast for Pope John Paul in 1978, according to the account, which Limessaid was from the diary of an unnamed cardinal.