Rio won the gold. So now what?

Played by heads of state, marketing jocks and heavyweight lobbyists, the game of winning the Olympic Games has become just as fierce as any contest on the track or in the pool.

To win the 2016 games for Rio de Janeiro, Brazil spent some $50 million. It fielded the likes of Pelé, Paulo Coelho, a bestselling author, and the entire Brazilian diplomatic corps. Whereas President Obama, on behalf of Chicago, breezed into the meeting of the International Olympic Committee in Copenhagen, Denmark, minutes before the decision was taken Oct. 2. Brazil's president, Luiz Inacio Lula da Silva, spent two days there, having earlier written personal letters to the 106 voting members and had each hand-delivered by an ambassador.

Why did Rio win? "We wanted it more," said Carlos Roberto Osorio, of Brazil's Olympic committee.

That was the easy part. Holding the Games will require effort and expense on a scale that Rio, a problem-studded metropolis of 12 million (half of whom live in the city itself), has never seen. Apart from new stadiums and other sports facilities of all kinds, the plans call for new bridges and roads and a doubling in the number of hotel rooms.

To revamp a chaotic transport system, engineers will blast through granite mountains to extend the metro from Ipanema to Barra da Tijuca, 8.4 miles away. Tens of thousands of athletes must be squired to scattered events through some of the worst traffic in the Americas.

The police, already overstretched, must keep the Olympians safe from some of Latin America's most brazen criminals -- they committed more than 2,000 murders in the city itself last year. Where padding public-works contracts and sticky-fingered politicians are the norm, who will make sure the $14.4 billion budgeted for the Games will be put to good use -- to say nothing of up to $50 billion in indirect investment?

There are plenty of skeptics, not least in São Paulo, Brazil's financial and industrial center, where Rio is often dismissed as a party town. The Pan American Games held in Rio in 2007 reportedly cost 10 times the official budget, and left behind underused arenas.

But there are reasons for hoping that Rio might just succeed where other places have failed in imitating the achievement of Barcelona, Spain, which used 1992's Games to reinvent a city. Rio has been declining for half a century, since it lost its status as the national capital to Brasília. For most of this time, the city and surrounding state have been poorly governed and brutally and badly policed. Manufacturing and banks moved to São Paulo, and the only growth industries seemed to be drug-trafficking and gang warfare. One in six Cariocas is poor.

Some things are improving, partly as a result of Brazil's stronger economy. Offshore oil is injecting revenue. Poverty is falling and property is booming. Often at odds in the past, the city, state and federal governments united for the Olympic bid. The new transport lines promised for the World Cup and the Olympics are sorely needed. The white elephants of the Pan American Games will find a new use.

But will the Olympics regenerate Rio, or distort its priorities? The prospectus talks of redeveloping the decaying port area, and of at last cleansing Guanabara Bay of sewage and industrial pollution. But whereas Barcelona built its Olympic village in a derelict part of its port, in Rio it will be sited, along with many events, in Barra da Tijuca, a nouveau-riche neighborhood at the wealthiest end of the city.

During the Pan American Games, police and army troops flooded the streets, smothering crime. More useful would be to use the next seven years to coax violent young men to take up sport or to get construction jobs.

"Why don't we make eliminating poverty in Rio and pacifying all the violent slums our goal for 2016?" said André Urani of the Institute for Studies on Labor and Society, a think tank in the city.

For Brazil, the award of the Olympics, hard on the heels of the World Cup, is yet another symbol of its growing status in the world. As Lula put it in Copenhagen, Brazil is no longer a "second-class country." That may bring intangible benefits. It is now the job of Brazil's politicians to ensure that they outweigh the costs.