Like many people in Leavenworth, Kan., Jeff Fagan spent his career working in prisons.

The son of a corrections officer at Fort Leavenworth’s military prison, Mr. Fagan described going to work as a young man in Leavenworth’s silver-domed federal penitentiary. He later got a job at the state prison just outside city limits, where he said he spent nearly four decades as an officer.

So when Mr. Fagan heard about plans for a private company to run an immigration detention center in his city, it seemed like a natural fit. Leavenworth is a prison town, after all, and the company was offering a starting wage of more than $28 an hour.

“I’d like to see all the revenue that would come into our community, all the jobs,” Mr. Fagan said, adding that Leavenworth, which has 37,000 residents, is “not like a community that’s completely, totally afraid of the fact that you have prisons.”

But even in a place that has been in the corrections business for more than 150 years, plans for an immigration detention center have proved divisive, fusing national tensions into municipal debates.

City leaders filed two lawsuits against the detention center’s private operator, CoreCivic, after conversations about a local permit fell apart. A judge temporarily blocked the company from housing detainees. Lawyers and activists raised alarms about understaffing and violence when the facility last housed inmates.