With three major votes on the agenda, Olympic leaders begin weeklong meetings on Wednesday that will bring a close to Jacques Rogge’s 12-year reign as IOC president.

The International Olympic Committee convenes in Buenos Aires to choose a host city for the 2020 Games, elect Rogge’s successor and add a sport to the 2020 lineup.

First up, Rogge chairs his policy-making executive board for the last time, a two-day meeting to review a range of Olympic issues.

The full IOC then convenes starting Friday for its 125th session, a landmark meeting that will set the Olympic movement’s direction for the next decade.

On Saturday, the 100 or so IOC members will vote by secret ballot on the 2020 host, a three-way contest between Tokyo, Madrid and Istanbul. A day later, the members will choose between wrestling, squash and baseball-softball for a spot in the 2020 Games. And next Tuesday, the IOC will elect a new president from among six contenders.

After a two-year global campaign, Tokyo is seen as a slight favorite going into the final days of the 2020 race, pushing its case as a “safe pair of hands” at a time of global uncertainty.

With the leak of radioactive water from the tsunami-crippled Fukushima nuclear plant raising concerns, Tokyo bid leader Tsunekazu Takeda has written to all IOC members seeking to reassure them that the city and its Olympic plans are “completely unaffected.”

Madrid has picked up momentum in recent months, despite Spain’s recession and 27-percent unemployment rate. Madrid contends that its bid makes the most economic sense because most of the venues are already built and only $1.9 billion will be spent on construction.

Istanbul is urging the IOC to make a “historic” choice by taking the games to a new region and a city that links Europe and Asia. The bid has been scrambling to overcome the fallout from June’s anti-government protests and a slew of doping cases, while the civil war and chemical attacks in neighboring Syria underline the volatility of the region.

The prime ministers of Japan, Spain and Turkey will lead the bid delegations here, traveling to Buenos Aires from the G20 summit in St. Petersburg, Russia.

Wrestling looks in strong position to win back its place for 2020 after being surprisingly dropped from the list of core sports in February by the IOC executive board.

Stung by the wake-up call, wrestling body FILA responded rapidly by changing leadership, giving women and athletes a bigger role in decision-making and adopting rule changes to make the sport more fan-friendly.

Men’s baseball and women’s softball, which have been out of the Olympics since the 2008 Beijing Games, have merged into a single federation to improve their chances for reinstatement. Squash is back for a third try at making it into the Olympics.

IOC vice president Thomas Bach of Germany has been considered the longtime front-runner to succeed Rogge, the Belgian surgeon who served one eight-year term and was re-elected in 2009 to a second and final four-year mandate.

Richard Carrion, a Puerto Rican banking executive who heads the IOC’s finance commission and vice president Ng Ser Miang of Singapore shape up as the other main contenders.

Also on the ballot are executive board members Sergei Bubka of Ukraine and C.K. Wu of Taiwan and former board member Denis Oswald of Switzerland.

Bach, a 59-year-old lawyer, is a former Olympic athlete, winner of a team gold medal in fencing in 1976. He has served at the top levels of the IOC for years and is president of Germany’s national Olympic committee.

Some members are uncomfortable with the pro-Bach lobbying by Sheik Ahmad Al-Fahad Al-Sabah, the influential Kuwaiti who heads the Association of National Olympic Committees. But Bach downplays the connection.

“I would, of course, be more than happy if the national Olympic committees would support me because I am an NOC president,” Bach said in telephone interview last week with The Associated Press. “But that is not enough. I want to be a president for all. You need the support from many different sides.”

The IOC is looking into comments made by Sheik Ahmad in a German television interview five months ago and aired last weekend. He openly expresses support for Bach and says he is doing everything he can to help him get elected.

Such comments are against IOC election rules. Sheik Ahmad could receive a warning or reprimand from the IOC ethics commission, though no severe sanctions are expected.

Carrion, the 60-year-old head of Puerto Rico’s Banco Popular, has earned respect as the IOC’s money man. He negotiated the record $4.38 billion deal with NBC for U.S. TV rights through 2020. He impressed members with his emotional notes-free speech during presentations by the six candidates in Lausanne in July.

“They liked what they saw. They liked what they heard,” Carrion told the AP. “I’m happy with what I’ve done. I’m following my plan. I’m where I wanted to be at this point.”

Ng, a 64-year-old businessman and diplomat, organized the inaugural Youth Olympics in Singapore in 2010 and represents an Asian continent that is growing in world influence.

“I believe in my heart that I have the independence, the integrity, the leadership qualities and the required experience to take the movement to new levels over the next eight years,” he said in a letter to IOC members last week.

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