We will find the money to do this because we can’t afford not to.

Geoffrey Canada strides to the lectern in the New York Sheraton’s Grand Metropolitan Ballroom amid the clatter and clink of laden plates and silver coffee urns, as 1,400 sets of eager eyes and ears–fans and acolytes, students and advocates, civic leaders, law enforcement officers, school chiefs, nonprofit staffers and a handful of funders representing 106 communities across the United States–turn their attention away from their sliced-chicken-and-asparagus entrees to the tall, lean man at the front of the room. The diners are gathered at a conference called “Changing the Odds.” They are there because they seek to glean the secrets and wisdom of the Harlem Children’s Zone (HCZ), Canada’s all-encompassing neighborhood anti-poverty program.

And they are not alone in listening closely to what Canada has to say. His grand experiment, which began in 1994 as an intensely local web of cradle-to-college social services and has expanded to include two charter schools and 97 square blocks of central Harlem, is about the hottest commodity on today’s national urban-policy scene.

Just a few weeks after the conference, Canada was featured in a glowing 60 Minutes portrait—the second time the premier TV newsmagazine has covered the Zone. Oprah Winfrey calls Canada “an angel from God.” ABC’s Good Morning America, PBS’s Charlie Rose and CNN’s Soledad O’Brien have broadcast Canada’s message; National Public Radio’s Terry Gross and Tavis Smiley have interviewed him; Public Radio International’s This American Life aired a lengthy profile; and articles about the Harlem Children’s Zone have appeared in The Wall Street Journal, U.S. News & World Report, Newsweek and other leading publications. In 2004, the Harlem Children’s Zone’s first charter school caught the attention of author and New York Times magazine editor Paul Tough, whose book-length profile of the Zone, Whatever It Takes, was published in 2008.

Think tanks right, left and center have discussed and evaluated Canada’s work. President Bill Clinton has paid homage; Britain’s Prince Harry and Prince Seeiso of Lesotho visited last May. A report last spring by two Harvard scholars asserting that Canada’s charter schools have eradicated the long-entrenched achievement gap between black and white students cued an ongoing avalanche of praise from pundits, cheer-led by Times columnist David Brooks’ celebratory accolade “The Harlem Miracle.” In 2007, Canada’s lifework was singled out by Barack Obama the candidate, and it has since been written into the President’s proposed 2010 and 2011 budgets as a template for Promise Neighborhoods, a program that aims to reverse generations of urban poverty and racial disparity. “We are launching Promise Neighborhoods to build on Geoffrey Canada’s successes in Harlem with a comprehensive approach to ending poverty,” the President has said. Of the cost, which Obama estimates to be “a few billion a year,” the President has vowed, “We will find the money to do this because we can’t afford not to.”

The Obama administration has already dedicated $10 million for planning grants, to be awarded competitively to 20 communities that will develop Promise Neighborhoods built on the Harlem Children’s Zone template. That’s what drew the audience that waited for Canada’s words at the Sheraton that afternoon in November.

Yet as Canada readily admits, his work has just begun. “We won’t have our cycle completed until 10 years from now,” he told the crowd in November. “It’s a 20-year cycle.” The Zone’s Promise Academy schools have posted celebrated gains on New York State standardized tests, but the schools are themselves too new to register a full complement of students or graduate a high school class. Many of HCZ’s social-service programs predate the schools, but their impact has mostly eluded measurement. The White House, prominent academics and the media have anointed the Harlem Children’s Zone the weapon of choice for attacking poverty, even though little is known about what degree of difference HCZ has actually made, and exactly how it was achieved.

There has been some success, no doubt. Canada possesses enormous integrity; his lifelong dedication is unquestioned. But it’s unclear whether the Harlem Children’s Zone is an exportable, adaptable commodity that can work from Cleveland to Compton or a “sui generis,” only-in–New York idea. Not every neighborhood could claim the deep, dense financial and political resources that have nurtured the Harlem Children’s Zone. Not everyone has a homegrown Geoff Canada to lead the way.

How much does a dynamic, charismatic, visionary leader matter?

Short answer: a great deal.