Without Le Corbusier and other Modernist visionaries, there could be no Robert Moses. Corbu, as he is familiarly known, adored cars, speed, high-rise towers, superhighways and superblocks. So did Moses. Corbu dreamed of clearing cities to the ground and starting anew. But it was New York's Moses who executed what the Modernists only imagined in their wildest fantasies.

To Hilary Ballon and Kenneth T. Jackson, the historians who put together a three-part, two-borough New York exhibition that reexamines Moses' legacy, his astounding run of completed projects was largely for the good of the region. In "Robert Moses and the Modern City," they take the heretofore heretical view that New York needed a wise tyrant to push the creaky metropolis into a lifesaving infrastructural upgrade.

"Had Moses never lived," Jackson asserts, "America's greatest city might have deteriorated beyond the capabilities of anyone to return it to prosperity."

It's a contentious statement from a contentious catalog that was written as a counterpunch to Robert A. Caro's famous biographical indictment of Moses. Yet not everyone is likely to reach the same conclusions simply by walking through the three venues. Indeed, after seeing the photographs of bustling neighborhoods that no longer exist and the crime-ridden look-alike towers that replaced them, I suspect that the blood of all but the most hardheaded pragmatists will be boiling.

Conceived on the scale of one of Moses' superblock projects, the exhibition covers his 26-year career as an unelected official at the helm of powerful, semiautonomous agencies that built everything from tennis courts to Lincoln Center.

Perhaps if you limit yourself to the offering at the Queens Museum of Art, "The Road to Recreation," which looks at Moses' early years as parks commissioner, you might be able to walk out feeling heartened by his contribution to the public realm. Rightly convinced that New York needed to soften the harshness of city life by providing leisure-time refuges, Moses went on a park-building spree. During the Depression-era summer of 1936, he cut ribbons on 11 public swimming pools, many designed with the care and nobility of a private club. That was the Good Moses.

But as his ambitions expanded, Moses bulldozed swaths of old New York in the name of clearing slums and providing highway links to mainland America. Tens of thousands of African American and immigrant families were booted out of their homes with little notice or compensation. Moses, like a good Modernist, loved to do his planning by taking a marker to a big aerial photograph of the city, oblivious to what happened on the ground. That was the Bad Moses.

Moses claimed the new infrastructure would keep New York competitive in the modern world. So it is especially tragic that too many of his projects left its neighborhoods worse off than before. The Cross-Bronx Expressway isolated the South Bronx and sealed its ruin, while Moses' penchant for sprawling housing projects without public streets created no-go zones where police feared to tread. Convinced that transit had no place in the car-dominated future, Moses shortchanged New York by refusing to build subways to the airports or alongside his highways. That lapse still has millions gritting their teeth daily.

Ballon and Jackson don't excuse all Moses' bad ideas, like his unrealized plan to run a highway through the middle of New York's Washington Square. But, like all apologists, they nick away at the margins without addressing the core issues. They argue that Moses was a product of his times who carried out widely accepted federal policies, much as Philadelphia's own master builder, Edmund Bacon, did. They claim that Moses doesn't deserve his despotic reputation because his contemporaries did worse.

The real question, which can never be satisfactorily answered, is whether New York would be better or worse off today without Moses.

While Caro's critical biography arrived in 1974, two years before New York's bankruptcy, when the battle to retain middle-class residents seemed hopeless, the exhibition comes when the city is flush with money, but frustrated by its inability to repair the open sore of ground zero. The organizers blame contentious interest groups for holding up progress and long for the strong hand of a Moses, who can get things done.

It's tempting to succumb to this argument. There's probably no city in America without a gaping planning failure - Philadelphia has Penn's Landing. And yet how many more Cross-Bronx Expressways would there be if citizens hadn't rallied against Moses' worst excesses? One man's pesky protesters are another's heroes. Imagine Philadelphia today if I-95 opponents had prevailed in Center City.

Would New York really have turned into a Detroit without Moses, as the organizers claim? When New York finally emerged from its '70s fiscal crisis, it was given a helping hand by a huge investment in transit and by urban pioneers who renovated factory lofts in neighborhoods that Moses targeted for slum clearance.

Jane Jacobs, Moses' nemesis, coined a lovely term for that activity. She called it "unslumming." If we're going to imagine New York without Moses, we should also try to imagine it without Jacobs and the pesky opposition.

If You Go

"Robert Moses and the Modern City" is on view in three parts:

"Remaking the Metropolis" runs until May 28 at the Museum of the City of New York. Information: www.mcny.org.

"The Road to Recreation" runs until May 27 at the Queens Museum of Art. Information: www.queensmuseum.org.

"Slum Clearance and the Superblock Solution" runs until April 14 at Columbia University's Miriam and Ira D. Wallach Art Gallery. Information: www.columbia.edu/cu/wallach.EndText