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Rarely, if ever, has so much been on the line at a single Olympic meeting.

When International Olympic Committee members gather next week in Buenos Aires, Argentina, they will be faced with three decisions that will shape the direction of the Olympic movement for the next decade.

At stake: Choosing the host city of the 2020 Olympics, electing a new IOC president to succeed Jacques Rogge and selecting one sport to add to the 2020 program.

The favorites: Tokyo, Thomas Bach and wrestling.

Prime ministers, royalty, sports stars and celebrities will be part of the election extravaganza at the IOC session. The weeklong meetings will have the flavor of a political carnival replete with last-minute campaigning, backstage vote-chasing and round-the-clock lobbying by spin doctors, consultants and strategists.

While most IOC members are primarily interested in the Sept. 10 presidential election, the first big vote comes on Sept. 7 with a secret ballot on the 2020 host city.

It's a three-way contest between Tokyo, Madrid and Istanbul.

All three are repeat candidates: Istanbul is making its fifth overall bid, Madrid a third straight attempt and Tokyo a second try in a row.

Tokyo has been seen as a slight front-runner, though the leak of radioactive water from the Fukushima nuclear plant is causing concern. Madrid — once counted out because of Spain's economic crisis — has picked up momentum recently and now looks like a legitimate challenger. Istanbul has slipped following the anti-government protests and doping scandals in Turkey and the escalating war in neighboring Syria.

With each bid facing political, economic or other drawbacks, the winner could be determined not for its positive attributes but for having fewer weaknesses than its rivals.

"There's no obvious choice," senior Canadian IOC member Dick Pound told The Associated Press. "Where do you go? None of the three is risk free. Probably somebody ends up backing into it this time."

Each city offers a different narrative. Istanbul would bring the games to a new part of the world, to a predominantly Muslim country for the first time, to a city linking Europe and Asia. Madrid has most of the venues ready and would spend the least. Tokyo offers safety and reliability at a time of global uncertainty.

In the end, the decision could center on which city offers the least risk. After taking gambles by sending the 2014 Winter Games to Sochi, Russia, and 2016 Olympics to Rio de Janeiro, some members feel it's time to opt for certainty. Delays in Rio are causing serious concerns and the IOC is eager to avoid more headaches.

"We're looking for the city which we can look toward to be the most secure option at this stage, given global uncertainties and the fact that we're entering into a new era with a new presidency," longtime Australian IOC member Kevan Gosper said. "We're looking for a safe pair of hands."

That sentiment works in favor of Tokyo, which hosted the games in 1964 and has repeatedly played up its case as being the "safe" choice. Tokyo also received the best overall review in an IOC technical report this summer.

"Of course we know how serious the Japanese are and we know they would deliver what they propose for sure," Swiss IOC member and presidential candidate Denis Oswald said.

The last few days and hours of the campaign could be vital. The final presentations on the day of the decision could swing a few votes that decide the outcome. Leading the bid delegations will be prime ministers Shinzo Abe of Japan, Mariano Rajoy of Spain and Recep Tayyip Erdogan of Turkey.

With a majority required for victory, the city with the fewest votes from the 100-or-so members is eliminated after each round. In this case, the vote is expected to go the maximum two rounds.

"I think the ultimate choice will be a matter of a difference of two, three votes, not more than that," Rogge said.

Members often vote for personal, sentimental or geographical reasons. Some will still be undecided when they get to Buenos Aires.

"IOC members vote with their hearts, not with their heads," veteran Norwegian member Gerhard Heiberg said. "They will look at the presentations and vote right there and then, not thinking that this is seven years ahead. That could decide who will take the gold medal."

Tokyo also can benefit from the sentimental factor of using the Olympics to help rebuild the nation's spirits after the 2011 tsunami and earthquake. Yet, it's the fallout from the disaster that is now posing the bid with its biggest challenge — the leak of radiation-tainted water into the Pacific from the crippled plant.

"Japan has got to recover from the real effects and perceived effects of the biggest nuclear meltdown since Chernobyl," Pound said. "That's not chopped liver."

Madrid's bid has been hindered by the economic meltdown in Spain, which has been mired in recession for most of the past four years and has a 26.3 percent unemployment rate. In addition, Rajoy has been embroiled in a party financing scandal, and Spain's record on doping and handling of the Operation Puerto case have dogged the bid.

But Madrid, and a speech by Crown Prince Felipe, made the biggest impact in presentations to IOC members in Lausanne, Switzerland, in early July. The Spaniards hammered home this point: The games pose no economic risk, 80 percent of the venues are ready, the construction budget will be only $1.9 billion ($10 billion less than Istanbul's).

The message resonates at a time when the Olympics are being criticized for being too expensive — the price tag for construction in Sochi is more than $50 billion. Madrid's strong showing in the 2012 and 2016 races also underlines its capability of securing votes.

Once seen as a favorite because of its compelling story line, Istanbul — which bid previously for the 2000, '04, '08 and '12 Olympics — has been scrambling to keep in contention after a tumultuous summer in Turkey.

Images beamed around the world of police using force on anti-government protesters in the heart of Istanbul in June rocked the bid. More than 30 Turkish track and field and other athletes were suspended for doping. FIFA complained of empty seats at the Under-20 World Cup in Turkey. Civil war continues to rage in Syria, with Western countries now weighing military action in response to suspected chemical weapons attacks.

Three days after choosing the host city, the IOC will pick a leader who will lead the organization through the 2020 Games for a term of eight years — and a potential second term of four years. Rogge is stepping down after completing 12 years in the job.

Making up the record six-man field are IOC vice president Bach of Germany; vice president Ng Ser Miang of Singapore; finance commission chairman Richard Carrion of Puerto Rico; executive board members Sergei Bubka of Ukraine and C.K. Wu of Taiwan; and former board member Oswald.

It shapes up as a three-man race, with Bach the favorite and Carrion and Ng the challengers.

Bach, a 59-year-old lawyer, has long been viewed as the man to beat. He ticks the most boxes: former Olympic athlete and gold medalist (team fencing in 1976), long-serving member on the policy-making board, chairman of the legal commission, head of anti-doping investigations, negotiator of European TV rights, president of Germany's national Olympic committee.

"If you were handicapping, you'd have him in front, but whether it's by a nose or a neck or open water, I don't know," Pound said.

The voting process is the same as for the bid cities.

Some of Bach's supporters believe he could win in the first round. If not, things could get trickier, as it's not clear where the votes will go in the next rounds. Wu and Bubka appear to be the most vulnerable of going out first.

If Bach is elected, he would continue Europe's hold on the presidency. Of the IOC's eight leaders, all have come from Europe except for Avery Brundage, the American who ran the committee from 1952-72.

Bach brushes off the pressure of being the front-runner and exudes confidence heading into the final days.

"I take this campaign like I prepared for a big competition as an athlete," he told the AP. "You know how important good training is, that it's very helpful if your test events are going well. This can give you confidence. But, on the other hand, all that does not count when it comes to the grand final. That is the same for Sept. 10. You want to see the competition taking place. I'm really looking forward to this day."

Wrestling, meanwhile, looks set to end its seven-month limbo and win back its place in the 2020 Games. The vote will take place on Sept. 8, with squash and a combined baseball-softball bid also vying for the single spot on the program.

Wrestling, featured in every Olympics except for 1900, was dropped from the list of core sports by the IOC executive board in February, a stunning decision that provoked an international outcry. The United States joined with unlikely allies Russia and Iran in fighting to save the sport.

Wrestling governing body FILA responded quickly, replacing Raphael Martinetti as president and electing Nenad Lalovic, adding two new weight classes for women and enacting rule changes to make the sport more fan-friendly. In May, wrestling easily made it onto the shortlist for inclusion in 2020.

"I have no doubt it will happen," Oswald said. "It was such a mistake. It has to be corrected."