CLEVELAND -- Cleveland envisions its Republican National Convention in July as an opportunity to show off its re-invented self and bury memories of default, industrial demise and a mayor who accidentally set his hair on fire.

Thanks to Donald Trump, Cleveland's first nominating convention since 1936 might not be the customary coronation and infomercial, despite a $64 million corporate fundraising pledge and $50 million in federal assistance to assure all goes smoothly.

"This has the potential to be very, very good for the city," said Stephen Loomis, president of the Cleveland Police Patrolmen's Association. "It also has the potential to be very, very bad for the city."

The prospect of a fight for the Republican nomination, bolstered by Trump's warning of riots if he doesn't get the nod, has evoked memories of raucous conventions from long ago when backroom deals by kingmakers often determined the nominee. Those featured fistfights on arena floors and, in Chicago's 1968 Democratic gathering, violent street disturbances that stained the city as images were broadcast worldwide.

The risk attached to the July 18-21 convention has revived the debate over the economic benefit derived from mega-events such as Super Bowls, NATO summits and the quadrennial gatherings to nominate Republican and Democratic presidential candidates.

"For Cleveland, the name recognition and having a chance to tell the turnaround story of downtown brings the potential reward of changing perceptions of the city," said Ned Hill, an Ohio State University economist. "If it turns out there is blatant Trumpism in the streets, then the good news story will disappear."

Downtown Cleveland, with streets torn up and utility trucks working around the Quicken Loans Arena, looks like it's getting spruced up for a big date with 50,000 convention-goers. The 116-year-old Electric Building high-rise, which now houses the United Church of Christ, sports a large banner that reads, "We have faith in Cleveland."

The possibility of turmoil wasn't imagined two years ago when the city of 390,000 people, beat out Dallas for the right to host the event. Conventional wisdom then suggested former Florida Gov. Jeb Bush would coast to the nomination, giving Cleveland the chance to bathe in the positive light of national television exposure.

Trump's stunning rise, accompanied by violence at his rallies and his own bellicose remarks, has fueled an expectation of disorder. Roger Stone, a Republican operative and Trump ally, invoked the 1968 "days of rage" when he tweeted April 2 his plans to organize protests in Cleveland if Trump isn't nominated.

Texas Sen. Ted Cruz and Ohio Gov. John Kasich are trying to halt Trump's march, and the convention's approach has led to speculation that party officials will engineer the outcome, much as Cleveland Republican kingmaker Mark Hanna did more than a century ago.

No matter the machinations, boosters see the opportunity to showcase a Rust Belt city once dismissed as "the mistake on the lake" as irresistible.

"The fact this will be a hotly contested convention hopefully will bring more eyes to the screen," said Chrissie Fahey, who runs a popcorn shop about three blocks from the Quicken arena, the convention's home. "This is a brief moment in time for Cleveland."

David Gilbert, chief executive officer of the Cleveland 2016 Host Committee, said "this is the right time for the eyes of the world to be on our city."

"This city is so fiercely proud of being able to take a punch and get back up," said Gilbert, who also runs the Greater Cleveland Sports Commission.

Cleveland's absorbed lots of punches. It bled manufacturing jobs starting in the 1960s, and with them more than a half-million residents. The slide generated a steady flow of material for late-night TV jokes. The polluted Cuyahoga River caught fire in 1969, drawing national attention. In 1972, then-Mayor Ralph Perk accidentally set his hair aflame with a welder's torch during a ribbon-cutting.

Things got worse. Cleveland defaulted on $15.5 million in loans from banks in 1978, the first major city since the Great Depression to not meet its financial obligations. Since 1950, the population has plunged 57 percent, to 396,000. While the shrinking hasn't stopped, the city's economy is bolstered by growth in the health care and higher education sectors.

Standard & Poor's assigned the city a third-highest AA credit rating in October, with a stable outlook. The company cited Cleveland's diversifying economy and income-tax revenue as pillars of nascent strength.

The Rock and Roll Hall of Fame, which opened in 1995, has drawn more than 10 million visitors. The 2014 return of professional basketball star LeBron James to the hometown Cleveland Cavaliers has proved to be an emotional boost to the city. James is featured on a giant mural on a downtown building, his arms stretched wide in front of a crowd of adoring fans.

The Cavalier's home court will host the four-day convention. Perhaps appropriately, the venue has hosted World Wrestling Entertainment's SummerSlam, Unforgiven and No Mercy pay-per-view broadcasts.

"I have no fear that it'll be Chicago 1968, even if Donald Trump doesn't get the nomination," said Cleveland City Council President Kevin Kelley.

Kelley and others point to economic gains from earlier conventions, noting claims of $200 million-plus in spending, primarily from jammed hotels and restaurants during Republican events in Tampa in 2012 and St. Paul, Minnesota, in 2008. The counterweight is the potential of attention diverted from the city's early renaissance to chaos at Quicken arena.

"What you hear from Trump increases the level of anxiety, but we'll be prepared for whatever happens," said City Councilman Matt Zone, who heads the safety committee.

About 600 officers from Cleveland's 1,500 member police force will be on duty for the event, Loomis said, aided by as many as 2,500 security personnel from outside the city. Using $50 million in federal grants, Cleveland will purchase barricades, batons and 2,000 sets of riot gear.

Recent terrorist attacks in France, Brussels and San Bernardino, Calif., have added to the security concerns. The equipment hasn't been delivered, Loomis said, and his officers haven't been thoroughly trained.

"We were excited when we first heard about this," Loomis said. "But I'd be lying if I didn't say I was very concerned."