VATICAN CITY The cardinals who enter the papal conclave on Tuesday will troop into the Sistine Chapel in single file, but beneath the orderly display, they are split into competing lineups and power blocs that will determine which man among them emerges as pope.

The main divide pits the cardinals who work in the Vatican, the Romans, against the reformers, the cardinals who want the next pope to tackle what they see as the Vatican’s corruption, inefficiency and reluctance to share power and information with bishops from around the world.

But the factions in this conclave do not break along geographical lines, and in fact, they have produced alliances that are surprisingly counterintuitive: The Romans’ top preference appears to be a Brazilian, and the reformers are said to be pushing for an Italian.

This conclave is far more unpredictable and suspenseful than the last because the church landscape has shifted in the past eight years. The next pontiff must unite an increasingly globalized church paralyzed by scandal and mismanagement under the spotlight in a fast-moving media age. And among the cardinals, there is no obvious single successor to Pope Benedict XVI, who rattled the church by resigning last month at age 85.

With all of the uproar over Vatican scandals, the Romans are aware that they may fail if they back one of their own, and so they are said to be coalescing behind the Brazilian, Cardinal Odilo Pedro Scherer, the archbishop of Sao Paulo.

Scherer is of German heritage, but his selection would give the Roman Catholic Church its first pope from Latin America. The region is home to about 40 percent of the world’s Catholics, and the church is staving off challenges there both from surging evangelical churches and a drift toward secularism.

The reformers, led by the Americans and some influential Europeans, are reportedly uniting around the Italian, Cardinal Angelo Scola, the archbishop of Milan, a popular pastor and an erudite moral theologian. As an Italian, he is familiar with the culture that dominates the Vatican bureaucracy, but he is not a part of it or beholden to it.

Many cardinals, however, say they are eager for a pope from outside Italy and, better yet, from outside Europe, an appointment they hope would energize the world’s 1.2 billion Catholics.

Other front-runners could easily emerge in what is shaping up to be a fluid contest with ever-shifting alliances and priorities, according to interviews in the past week with church officials, and the scholars and journalists who study the church.

With the stage truly wide open, the next pope to appear on the balcony to address the crowd in St. Peter’s Square could be a compromise cardinal from Argentina, Canada, Hungary, Mexico, the Philippines or even the United States.

Whoever he is, he will have to convince his fellow prelates that his gifts as an evangelist and an administrator can move the church past the scandals involving child sexual abuse, the Vatican bank, the recent resignation of a cardinal who admitted he had used his own priests for sexual favors, and the so-called VatiLeaks episode in which the pope’s personal papers were stolen and published, revealing infighting in the church’s central administration, known as the Curia.

“The most perceptive cardinals understand that the evangelization of the church is obscured by the petty realities that represent the disorder of the Roman Curia,” said Sandro Magister, a Vatican analyst with the weekly magazine L’Espresso.

The last conclave eight years ago presented a far simpler scenario. There was one dominant candidate to beat going in, and that was Cardinal Joseph Ratzinger, the longtime head of the Vatican’s office on doctrine and the close collaborator of the previous pope, John Paul II. He was elected on the conclave’s second day after just four ballots and took the name Pope Benedict XVI.

“In 2005, it was, if not Ratzinger, who? And as they got to know him, the question became, why not Ratzinger?” said Austen Ivereigh, a writer on Catholicism from England and the former spokesman for retired Cardinal Cormac Murphy-O’Connor.

For the first time, an American could be poised to overcome the conclave’s traditional aversion to a pope from a superpower, though not all analysts agree on this. The most likely contenders are: Cardinal Timothy M. Dolan, the archbishop of New York, known for his exuberant presence and evangelizing skills; and Cardinal Sean Patrick O’Malley of Boston, a Capuchin Franciscan friar, who has a reputation for having calmed the waters in three successive dioceses (Fall River, Mass.; Palm Beach, Fla.; and Boston) ripped up by child sexual abuse scandals. Both have spoken out in favor of change.