Can the VA pull off its 'monumental' bid to end veteran homelessness?

For Denis McDonough, like generations of Veterans Affairs secretaries before him, homelessness among U.S. military veterans remains a confounding stain on America's promise.

"The American people expect that there not be homeless veterans. The bigger problem for us is going to be if we fail, which is why I'm not going to let us fail," McDonough told ABC News in an exclusive interview marking one year after being confirmed to the job.

While the number of homeless vets has dropped by more than half over the last decade, an estimated 20,000 ex-service members are still without permanent housing on any given night, according to figures released this month by the Department of Housing and Urban Development.

McDonough believes the VA and an alliance of private developers and nonprofit groups could be on the cusp of significantly reducing the number even further, starting in Los Angeles, California, which has more homeless veterans -- an estimated 3,900 -- than anywhere in the country.

"We really think that we can supercharge this effort so we can show the country that this is doable there," McDonough said. "We can then use that momentum to get it done everywhere else."

The West LA VA campus, a sweeping 388-acre plot set just to the west of Beverly Hills and UCLA -- some of the government's most valuable real estate -- is in the midst of an ambitious transformation to house a community of more than 1,200 veterans in permanent apartment homes.

First set into motion in 2015, it is the largest veterans housing project in the country.

Dozens of historic buildings -- most over 80 years old and currently in disrepair -- are slated for renovation into gleaming residences, community spaces, art and athletic facilities, libraries and career service centers.

Residents would have easy access to VA case workers, psychologists, psychiatrists, doctors and administrative support -- all on the same property.

"Community is crucial. Having people around you who share the same experiences can build resilience," said Tess Blanco, a Marine veteran and survivor of military sexual trauma, who is the campus' community director.

Blanco called the unprecedented integration of services with the housing "monumental."

"It is no doubt an emphatic answer to an intractable problem," said Steve Peck, a Vietnam combat veteran and president and CEO of U.S. VETS, the principal developer on the project.

"We can build as much housing as we want, but if the appropriate support services are not provided along with that, many of those veterans will become homeless again," Peck said. Roughly a third of veterans who receive housing vouchers from the VA return to the street at some point.

"If we can solve this riddle here -- of how to jointly provide these services on the campus -- then that can be replicated at other VAs across the country," said Peck.

ABC News got an inside look at the public-private development last month as construction was underway on nearly 200 apartments across three buildings, which the developers say will be completed later this year.

Blocks away on the property, dozens of homeless veterans are living in tents and tiny temporary homes -- a jarring reminder of how urgently the renovations are needed.

The progress has been slow going.

A draft master plan for the West LA VA development initially projected 490 permanent housing units for veterans would be completed by March 2019; but only 54 units -- or 5% of the goal -- have been finished since the plan was approved in 2016.

At the current pace, it would take more than 20 years to finish the campus as envisioned. An independent report by the RAND Corporation in 2020 faulted a lack of accountability and lack of urgency for the sluggish pace.

"It is a funding problem," said Peck. "The water, the sewer, the electricity, the telecom -- all of that has to be redone, and where is that money going to come from?"

Peck said developers have so far raised only about 10% of the total estimated price tag, roughly $100 million. He said the project has also been hamstrung by bureaucratic red tape. "When the top dog says, 'let's get it done,' then people below find a way to get it done," he said.

VA Secretary McDonough recently named an executive-level position in his office to directly oversee the project, but he said some of the time-consuming environmental impact assessments, public comment periods and other waypoints are required by law.

"It's a balancing act," McDonough said. "I don't think, at the end of the day, we're going to be at a lack of dollars or lack of resources. What we have to do is work through this transparently and in a way that we continue to maintain people's confidence."

Many advocates for homeless veterans told ABC News the 10-year or longer timeline to finish the construction on the West LA VA campus remains unacceptable.

"This is a humanitarian crisis," said Nicholas Cormier III, a former Air Force air traffic controller who spent time living at a shelter in Building 257 on the campus when he lost his job and couldn't pay rent. He now advocates for fellow vets stuck in similar situations.

"It's a war zone, it's -- you know what I mean?" Cormier said. "This is how I see addressing the problem: It's boots on the ground every single day."

Joyce Campbell, a Navy veteran and IT professional, had a good-paying job and a home until COVID cost her both. VA housing assistance has helped her reset, she said.

"It has allowed me to settle down my emotional state, you know, and get comfortable in looking forward as opposed to continually watching my back to make sure that something's going to sneak up behind me," Campbell said.

The West LA VA project's potential to make a big dent in veteran homelessness has drawn a small army of backers, including former chairman of the Joint Chiefs, retired Adm. Mike Mullen.

"This could be a model for many VA centers across the country," Mullen told ABC News in an interview. "And it is unique. There's no question about that."

"I've been involved in this project with four secretaries," Mullen said. "So it becomes very difficult to hold them accountable. I would love to see Congress much more involved."

Secretary McDonough -- only the second person without military experience to lead the VA -- has personally intervened to expedite the effort. On a visit to LA late last year, he publicly vowed to help house 500 local homeless veterans by the end of the year -- a promise he kept by most accounts.

Last month, ABC News accompanied McDonough as he joined the nationwide "point-in-time" count of America's homeless in cities coast to coast, an annual effort led by HUD and the VA to get an accurate picture of the problem.

"I'll tell you what, walking around in some tough neighborhoods on as cold a night as we've had in D.C. is a good reminder of just how difficult it is to be homeless," he said.

"I've been very clear that I should be held to account for this," said McDonough of the initiative. "What remains is elbow grease, and we're going to apply the elbow grease. And if it's not applied, then it's my problem."