Detroit (CNN) Six years after Detroit filed for the largest municipal bankruptcy in US history , the Motor City is roaring back to life.

The bankruptcy is in the rearview mirror. New development, spearheaded by Quicken Loans' billionaire founder Dan Gilbert, has transformed the downtown core. Fiat Chrysler recently announced plans to open the first auto assembly plant in Detroit in nearly three decades, bringing 5,000 jobs to the city.

And this week, Detroit will get fresh attention when 20 Democratic candidates descend on the city for the second set of presidential debates of the 2020 election -- putting a spotlight on its rebirth and the struggles it still faces.

The Democratic National Committee-sanctioned debates, airing over two nights on CNN, also underscore the political clout of this Rust Belt state. Michigan twice voted to send Democrat Barack Obama to the White House before backing Republican Donald Trump by the narrowest of margins in 2016.

Detroit's rebound "is one of the most underrated stories in the nation," said veteran Michigan Democratic consultant Joe DiSano, who grew up outside Detroit in Macomb County, a traditional bellwether that backed Obama before flipping to Trump.

"There's an amazing pride among Michiganders in the resurgence of Detroit because as Detroit goes, so goes the state," he said.

The People Mover, an above-ground transit system built in the the late 1980s, circles downtown Detroit as construction crews work on Hudon's site, a mix-used development. It is planned to be the tallest building in Michigan's history.

"Detroit is not as bad as it used to be, but it's still not where it should be," said Luther Keith, a former Detroit News editor and columnist who now runs ARISE Detroit! , a neighborhood revitalization group.

The Democratic presidential candidates "are coming to the epicenter of hope and despair at the same time," Keith said.

A new presidential battleground

In 2016, Trump became the first Republican presidential contender to win the state since 1988, defeating Democratic nominee Hillary Clinton by fewer than 11,000 votes out of 4.8 million cast.

The road to the White House in 2020 runs through Michigan and the other Rust Belt states Trump captured to score an Electoral College victory even as he lost the popular vote to Clinton. Most political observers agree the Democratic presidential nominee likely would have to carry Michigan and its 16 electoral votes to deny Trump a second term.

It's no surprise, then, that Republicans and Democrats are gearing up for an epic battle in the state.

Priorities USA Action, the main Democratic super PAC focused on the presidential race, plans to spend $100 million to persuade voters in Michigan and three other battlegrounds -- Florida, Wisconsin and Pennsylvania -- to reject Trump. This month, it launched a new round of digital ads in Michigan and other targeted states.

The Michigan Republican Party, meanwhile, says it's now building its largest field operation ever in a presidential election, as it works to tie the state's economic recovery to Trump and his policies.

Crystal Daniels and her 3-year-old daughter, Mikayla Daniels, gaze out at passing cars while hanging out on their front porch with Crystal's father, Wayne Daniels, on the city's west side. Wayne has lived in the neighborhood for over 30 years.

"Both sides are treating (Michigan) as though it's absolutely critical," said Tom Shields, a Republican consultant in Lansing. "Democrats can't afford to lose it, and Republicans would love to win it."

In his attempt for another campaign victory in the state, Trump could face stiff headwinds.

Michigan Democrats made big strides in the 2018 midterm elections, winning the offices of governor, attorney general and secretary of state and picking up two US House seats. Macomb County, which swung to Trump in 2016, backed successful Democrat Gretchen Whitmer in last year's governor's contest.

One of the new faces in Michigan politics this year is a top Trump target: liberal Democratic Rep. Rashida Tlaib, who was elected from a Detroit district long represented by John Conyers. Tlaib, one of just two Muslim women elected to Congress, has repeatedly called for Trump's impeachment. He's repeatedly attacked her and three other freshmen House members. This month, he tweeted that the four women of color -- known as the "squad" on Capitol Hill -- should "go back" to their countries, drawing a formal rebuke from the House of Representatives.

This week's debate, in Detroit's historic Fox Theatre, will take place in Tlaib's district, which includes parts of east Detroit, some of city's western suburbs and a chunk of downtown.

Downtown explosion

Gilbert, whose Quicken Loans is the nation's largest mortgage lender, is central to Detroit's resurgence.

The Detroit native bet big on the city in 2010 when he decided to move his corporate headquarters and 3,400 jobs to the heart of Detroit. Crime was so bad in the beginning that the company set up its own security "command center" to ensure workers' safety, said Bill Emerson, the vice chairman of Quicken Loans and CEO of Bedrock, the real-estate arm of Gilbert's empire.

Today, Gilbert's network of companies employs 17,000 people in Detroit, and Bedrock owns more than 100 buildings in the city, most of them in the downtown core.

"Detroit is just a tough, gritty city," Emerson said. "Dan has said this for years: 'It's at the intersection of muscle and brains.' It's an area of the country where folks understand hard work ... They are passionate about and committed to their city."

Nowhere is Detroit's resurgence more evident than along the downtown stretch of Woodward Avenue, Detroit's main thoroughfare.

National chains, such as eyeware retailer Warby Parker and fragrance store Le Labo, now occupy storefronts that struggled to attract shoppers a decade ago.

Roslyn Karamoko is the owner and founder of Detroit is the New Black. The downtown space also houses merchandise from other artists, entrepreneurs and fashion designers of color.

Tucked among them, in a Bedrock-owned building: Détroit is the New Black , a sleek boutique and exhibition space owned by local designer Roslyn Karamoko.

The Seattle native moved to Detroit in 2013, following stints in Washington, DC, Singapore and New York, where she was a fashion buyer. When she first relocated, friends told her, " 'Detroit's so scary. Why are you moving there?' " Karamoko recalled.

"But it's great," she said. "The American Dream story is still possible here."

"I started this literally selling a few T-shirts to friends," she said, standing in the middle of her store, where she carries everything from the $29 T-shirts that bear her brand's name to $2,300 couture dresses.

"I don't think you can do this in any other city," Karamoko said.

The redevelopment also is changing other close-in parts of Detroit.

The QLINE, a street car funded by Quicken and a cluster of other businesses and private foundations, now connects the city center to Midtown, another rapidly transforming area. A former skid-row district once known as Cass Corridor, Midtown today is dotted with loft apartments, a bar promoting its "artisanal ale" and a fashionable farm-to-table restaurant where diners can sip craft cocktails and eat seared octopus and beef tartare.

'Motors, mortgages and pizzas'

Gilbert isn't the sole investor in Detroit.

The Ilitch family, which made its fortune with the Little Caesars Pizza chain, is a longtime force in the city. The family owns the Detroit Tigers, the Red Wings, Little Caesars Arena , and the opulent, 1920s-era Fox Theatre.

People dine at Selden Standard, an upscale restaurant in Midtown, also known by natives as Cass Corridor. The building was once an abandoned laundromat.

Chad Livengood, a senior editor at Crain's Detroit Business who has covered the city's bankruptcy and recovery, said some are wary of Detroit's heavy reliance on the auto industry and two wealthy families.

"We're kind of basing the future on a few specific industries: Motors, mortgages and pizzas," Livengood told CNN.

"My concern is that we are just going to be susceptible to the same boom-and-bust cycles that have afflicted Detroit in the past. We haven't quite diversified our economy enough to handle another long recession."

The Detroit business community also is closely attuned to health news about Gilbert, who had a stroke in May.

In the interview with CNN, Emerson said Gilbert, 57, is "making great strides" in his recovery. "Dan will be back, fully functioning," he said. "It's just a matter of when."

Burned-out homes, empty lots and ...hope

A drive through Detroit reveals a patchwork of prosperity and poverty. Newly built luxury apartments and stately Tudor mansions erected by auto barons in the last century sit within a mile or two of burned-out frame houses.

On some streets, empty lots -- overrun with tall grass and brush -- outnumber homes, giving pockets of inner-city Detroit a strangely rural feel.

The two-apartment house where Keith, 68, grew up in Detroit's near west side, is gone, lost to fire years ago. On the neighboring lot, runaway ivy scales the walls of a crumbling house.

Luther Keith, the executive director of the non-profit Arise Detroit, stands on an empty lot where his childhood home once stood. The home is said by neighbors to have burned down in the '90s.

In his day, the working-class neighborhood was "an urban Mayberry," Keith said, filled with children playing baseball in the alley as parents headed to the auto plants for work. His father was a postal clerk.

"It's heartbreaking to see what this has become," he said, standing in the middle of his old street.

Decades of setbacks -- the long decline of the auto industry, riots in 1967, white flight to the suburbs, the collapse of city services -- dramatically altered both Keith's street and what was once the nation's fourth largest city.

Paige Field, 30, grew up across the street from the lot where Keith's home once stood and still lives there with her mother as she studies to become a licensed practical nurse. Amid all the decay, she sees signs of change.

"We see people coming in and buying the houses," she said, gesturing to one abandoned home where a new owner has boarded up the windows and front door.

A few miles away, two other native Detroiters, Darryl Chatman and Mike Nolan, sit outside a neighborhood soul food restaurant, taking a late-afternoon breather from their cleaning and construction business.

Business for the duo is booming, Nolan said, as investors -- some of whom live overseas -- buy houses "in bulk" all over the city.

"People don't understand how great Detroit is," said Chatman, who returned to the city three years ago after 15 years in Birmingham, Alabama. "It's a hard-working city. You can always get your hustle on here. I think of it as a diamond in the rough."

Keith has high hopes for his native city, too.

The weekend after the presidential debate, ARISE Detroit! will stage its 13th annual neighborhood action day. It's a chance, Keith said, for people in all parts of Detroit to put their stamp on the city's revival. Events range from school-supply drives and painting projects to helping to weed urban gardens.

"The Detroit comeback story is still being written," he said.