In Milwaukee, one of two cities vying to host the Republican presidential convention in 2024, Democrats were pilloried by the potential visitors after predawn election results delivered Wisconsin for Joe Biden in the 2020 White House race. Rival Nashville is run by a mayor whose Democratic brother was effectively redistricted out of his congressional seat by Republicans.

It’s safe to say those two Democratic strongholds have mixed feelings about landing the GOP convention. Hosting the once-every-four-year assembly is an immediate spending jolt, plus a few days of invaluable national exposure. But it also means rolling out a welcome mat for bitter political foes.

“Some people don’t want to see this happening,” the Milwaukee county executive, David Crowley, a Democrat, said. “Some people are holding their nose about bringing this to Wisconsin. But when you set politics aside, this is how we’re going to jumpstart our economic activity in southeastern Wisconsin.”

The cities made their final pitches to the Republican National Committee in Washington last week and a final decision is expected soon. It may rest on whether Republicans see more value in the honky-tonk-infused branding that Nashville offers as a way to connect with the white working-class voters likely to be at the center of the 2024 general election — or the chance to stake a claim to Wisconsin, a perennial presidential swing state that has its fair share of those voters in play.

Wisconsin could determine who wins in 2024, while Tennessee has not backed a Democrat for president since 1996. In the convention contest, history would seem to favor Milwaukee. For two decades, Republicans have placed their nominating convention in swing states — North Carolina, Ohio, and Florida.

President Trump beat Mr. Biden by 23 percentage points in Tennessee, while Mr. Biden won Nashville by 32 points. Yet the state GOP chairman, Scott Golden, said choosing Nashville would let Republicans highlight a GOP state that has continued to grow even through the pandemic, while attributing successes to business-friendly state tax policies, including no personal income tax.

Backers also argue that Music City is a more enticing getaway for attendees. The arena and convention center are a block away downtown. The Country Music Hall of Fame is across the street. The arena dumps attendees onto the famed neon-lit strip of bars, with live music at almost all hours. Hot chicken and biscuits are never far away.

New hotels are changing the skyline in and around downtown. Mr. Golden said convention-goers could be more concentrated in the city core, minimizing the long bus rides and distant lodging of previous conventions and dialing up the branding opportunity.

“This is really a very good narrative of America,” Mr. Golden said. “Obviously, it doesn’t hurt that the country music world is also centered there.”

Wisconsin counters that the 2024 gathering, just like the past three Republican conventions, should be in a crucial swing state. Boosters are playing up the opportunity, with Democrats like Mr. Crowley joining Republicans including Senator Johnson and a one-time Trump White House chief of staff and former RNC head, Reince Priebus, in making the pitch.

Milwaukee is also pitching itself as turnkey-ready thanks to its work to land the Democrats’ 2020 convention, though that wound up mostly online due to the coronavirus pandemic.

Still, Wisconsin’s polarized politics are evident even amid the bipartisan push.

Mr. Trump fought unsuccessfully to disqualify thousands of voters in Milwaukee in 2020, falsely portraying late-arriving returns driven by heavy absentee turnout as fraud.

The city’s top election official, Claire Woodall-Vogg, tweeted in mid-March that if Milwaukee gets the convention she would work remotely that week “lest I be hung in the town square like some have threatened.” Three days after she posted that message, she deleted her Twitter account.

Ms. Woodall-Vogg told the Milwaukee Journal Sentinel that her tweet was “an ill attempt at some dark humor given that I get death threats that are fueled by the 2020 presidential election.” Like other conflicted Democrats, she said she would welcome the convention for its positive economic impact.

“It’s a polarizing convention,” a Democratic state senator, Tim Carpenter, said. “Any time Donald Trump is in the party, it will make it a very polarizing type convention.”

Peggy Williams-Smith, who as head of the city’s tourism bureau has helped lead the city’s bid, said the convention should be about the economic impact to the city, state and region.

“This to me is not red or blue, it’s green,” Ms. Williams-Smith said.

The Nashville Convention & Visitors Corp. has sounded the same note, saying its job is to book conventions “without bias,” and pointing out it has also bid for the Democratic convention, both at the GOP governor’s request.

Mayor John Cooper, a Democrat, watched this year as Republicans divided the city three ways during redistricting, a move aimed at improving their chances to flip a Democratic congressional seat and one that drove Mr. Cooper’s brother, Representative Jim Cooper, not to seek re-election.

John Cooper told the Associated Press that there is a “whole lot of homework” to be done about hotel rooms and security concerns. He said the RNC is probably “getting a little bit of sticker shock” on how much Nashville hotels cost. He promised that “we are not going to expect our hospitality industry to take a loss in order to have this.”

Mr. Cooper said there’s a “different burden” with having all convention facilities downtown. He said Nashville police need to “feel really good about this for the application to go any further.”

Tennessee’s governor and GOP lawmakers may use state money to help pay for convention, if Nashville is selected.

Some Nashville Democrats say the event is not worth it, politically or practically.

A state representative, John Ray Clemmons, worries about the local government incurring costs and having to shut down sections of a city that will draw visitors regardless. The politics don’t make any sense, either, he said.

‘This is a beautiful, growing, and welcoming city,” Mr. Clemmons said. “And our city stands for everything that they oppose.”

As for whether the convention location will give Republicans a boost, a political science professor, David Schultz of Hamline University in St. Paul, Minnesota, isn’t convinced. He studied convention locations from World War II onward and found no evidence to support an effect on the outcome of races.

“There’s this political folk wisdom out there that placing a convention in a state will somehow either flip the state from being Democrat to Republican or vice versa, or somehow really energize the base in some way,” Mr. Schultz said. “Largely, it doesn’t work out.”

By SCOTT BAUER and JONATHAN MATTISE