David Bing, a businessman and former all-star basketball player who entered politics late in life, says he has no choice.
The 2010 census is expected to reveal a population of about 800,000, down from a peak of 1.8 million in the Motor City heyday of the late 1950s.
The long decline of the car industry and all its spin-off business has been exacerbated by the collapse of a housing market that has left prices close to what they were 50 years ago, when lifestyle magazines featured Detroit as the most desirable city in the United States.
Decent three-bedroom homes can be bought for $10,000, but no one wants to buy.
Decades of poor and at times corrupt administration have also taken their toll, and with the city facing a deficit of between $85 and $124 million this year, the answer, says Mr Bing, is to accept reality and reduce the size of the city.
"There is just too much land and too many expenses for us to continue to manage the city as we have in the past," he said. "If we don't do it, this whole city is going to go down."
Plans currently being devised would be the most revolutionary carried out by a major American city.
Large chunks of neighbourhoods would be razed and converted to parks, urban farms or simply abandoned. As an opening bid, Mr Bing has vowed to demolish 3,000 homes this year, and a further 7,000 over the following three years. Some are speculating that up to 40,000 homes could eventually go.
The plans are being watched by influential figures who believe other cities - including Philadelphia, Pittsburgh, Baltimore and Memphis - could follow suit. The Obama administration is being advised by Dan Kildee, who pioneered the policy in Flint in his role as treasurer of Genesee County.
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In Detroit's Brightmoor neighbourhood on the city's northwest side, it is easy to see the logic of his vision. On many blocks only two or three homes are inhabited, the rest have been vacated by repossession, abandoned or burned down by arsonists. They become magnets for rodents, rubbish or drug gangs.
The mayor has said that some people will have to move as more viable parts of neighbourhoods are built up and others flattened.
This has prompted cries of "ethnic cleansing" and "cleansing of the poor", accusations that defenders of the idea say ring hollow in a city that is 85 per cent black, whose top officials are mostly black, and where poverty rates are way above the national average.
Brightmoor resident Monique McLean, 29, would welcome the chance to be relocated. "It is terrible here, there's nowhere for kids to play and I don't fee safe at night. People have moved out and soon there will be no one left on the street," she said, standing outside her three-bedroom home. "I would be glad to get out of here. I would be glad to get out of Detroit, period." At one end of the street lies an abandoned car, and at the other a home gutted by fire with a three-piece living room suite rotting on the front yard. Every shop on a half mile stretch of high street nearby is shuttered. Even the pawnshop has closed down. Only three small Christian ministries are open for business.
Saving Detroit will be a mammoth effort. Almost a third of the city's 139 square miles is vacant or derelict, though its land area would comfortably fit Manhattan, San Francisco and Boston, cities with combined populations of three million.
By reducing the amount of the space the city serves, millions of dollars would be saved, said Charles Pugh, president of the city council, and other areas improved.
"We have to police property, put out fires, light the streets, pump water and shovel snow for all these sparsely populated areas where people really shouldn't be living," said Mr Pugh, who revealed shortly before his election last year that his own home had gone into foreclosure. "It's really, really inefficient." John George, a native of the city's northwest side, has been campaigning to improve blighted neighbourhoods for 21 years and describes Mr Bing as a "breath of fresh air".
Through his non-profit group Motor City Blight Busters, Mr George has founded a community centre near Brightmoor in Old Redford, financed a city garden, an art gallery, a restaurant and will soon open a jazz café. In the 1990s the group refurbished homes; now it mostly demolishes them.
"Why spend $50,000 on doing up a home that won't sell for $20,000? With the economy the way it is, we don't have time to wait. A lot of these areas are almost vacant now. To do otherwise would be like going to the dentist when you only have three teeth in your mouth. What's the point?"