'There Have Never Been as Many Poor People in Our Country as There Are Now'

"That was predicated on demonstrating that there were hard results," Mangano said. "That line of argument is essential in building political will and sustaining it. That's what will get the job done. You need to be able to muster the argument of investment leading to results."

Showing that investments worked with research and data to back it up, he said, was the "best inoculation against cuts."

The approach drew plaudits from mayors on both sides of the aisle as they implemented 10-year plans in their cities. In Chattanooga, Tenn., the smallest city to participate in the seeding stage of the housing-first initiatives, homelessness ended for nine out of 10 of the most vulnerable chronically homeless.

These mayors, many Democrats, wanted Mangano to stay on through the Obama administration, he said. But the new president wanted to change course.

"I served the first 100 days and they eventually told me that they wanted to have their own team," Mangano said. Obama's transition team told him "we appreciate what you did, but we just want our own team."

A Boston native, Mangano returned to Massachusetts where he would become president and CEO of the American Round Table to Abolish Homelessness, a role in which he continues to collaborate with mayors and governors to formulate and implement strategies shaped by cost studies and cost-benefit analysis with a focus on one final, tell-all metric: decreasing the number of those without a roof over their heads.

"Many faith-based nonprofits get a new vision of what their calling is, which isn't to manage homelessness but to end it," Mangano said of how the public mindset is evolving "from simply expending to investing."

He hopes that the lessons learned from the first decade of this century continue to be applied moving forward by the White House and "that rhetoric is undergirded by investment only in the most substantive ideas."

"If those basic business principles are not sustained it is possible that the rhetoric goes a bit hollow again," Mangano said.

And resources allocated to the homeless in Obama's stimulus plan, rapidly placing those who fell out of the housing market into new housing, have been exhausted.

"I don't think anyone thought the recession would last as long as it has," Mangano said. "The sustained nature of the recession and the inability to pull out certainly is a factor in the number of homeless families we're seeing."

Far from Americans suffering from compassion fatigue, he said he believes that the recession has given many a new understanding of the challenges faced by the poor -- and perhaps a "solution fatigue" in which those dedicating their lives to helping the less fortunate want to see results.

"People who themselves are teetering because of the recession increased their compassion because they have a new understanding of how vulnerable we are," Mangano said.

But the former homelessness czar said he's seen the 10-year plans formulated in those years offer "inspiration and remobilization" to communities as they see results from the business-oriented strategies. It tells communities if they "not only approach problems with their hearts but their heads they can make progress."

Mangano sees on the horizon great opportunity to scale what we now know works to bring an end to chronic homelessness by virtue of private investment.

"We have to think not only about best practices," he said. "We have to be thinking about next practices."