CHICAGO (WGN) — A total of 21 Chicago police officers were sent home and placed on no-pay status this week over their refusal to comply with a city order that employees disclose their vaccination status. The mandate has highlighted a tense relationship between the mayor and the Chicago police union that was brewing before the pandemic started.

“Fundamentally, what this is all about is saving lives. It’s about maximizing the opportunity to create a safe workplace,” Mayor Lori Lightfoot said of the mandate last Monday — the same day the Chicago Police Department started placing noncompliant officers on no-pay status and stripping them of police powers.

And though police unions across the country have voiced opposition to various vaccine mandates, the disciplinary measures lodged against Chicago cops are the latest point of contention in a long-running spat between the mayor and the Fraternal Order of Police, one that has hallmarked much of her first term.

Two months after her inauguration, Lightfoot was caught on a hot mic referring to a former union vice president as a “FOP clown.” Last year, she voiced her support for requiring officers to be licensed. She publicly chided several officers who were seen on surveillance video relaxing in the South Side office of Rep. Bobby Rush (D-Ill.) during the unrest and looting in the wake of George Floyd’s murder by a Minneapolis police officer. All the while, CPD officers were working without a contract.

A new police contract was entered last September — four years after the previous contract expired — but little else has helped to thaw the otherwise icy relationship between Lightfoot and the FOP, led by John Catanzara, a vocal supporter of former President Donald Trump and frequent critic of the mayor.

In May, the union issued a no-confidence vote in Lightfoot, CPD Supt. David Brown and First Deputy Supt. Eric Carter over their “lack of consideration” for officers’ working conditions, the union said.

The following August, CPD officer Ella French was shot and killed in West Englewood. Her partner, officer Carlos Yanez Jr., was also wounded by gunfire. Tensions between City Hall and the police were put on full display when Lightfoot showed up at the University of Chicago Medical Center, where French and Yanez were taken after they were shot.

Yanez’s father — himself a retired CPD officer — told the mayor’s staff that the family did not want her there. When Lightfoot showed up, CPD officers gathered at the hospital turned their backs on her.

Subsequent slips of the tongue by both Lightfoot and Brown only further incensed CPD rank-and-file. Speaking at a budget town hall meeting a few days after French’s death, Lightfoot referred to her as “Ella Franks.” At a news conference at CPD headquarters, Brown referred to French as “Ella Fitzgerald.”

That same month, Lightfoot ordered that every city employee be fully vaccinated by Oct. 15. The order was later revised to allow non-vaccinated city employees to remain on the job if they agreed to twice-weekly COVID-19 tests on their own time and at their own expense. But still, the order required all city employees to be vaccinated by the end of 2021, and the Oct. 15 reporting deadline remained.

Catanzara, meanwhile, strongly urged union membership to ignore the mandate. Speaking to the Chicago Sun-Times, he compared the city’s vaccine mandate to the Holocaust, during which the Nazis killed six million Jews and millions of others during World War II.

“We’re in America, g-ddamnit. We don’t want to be forced to do anything. Period,” Catanzara said. “This ain’t Nazi f—ing Germany, [where they said] ‘Step into the f—ing showers. The pills won’t hurt you.’ What the f—?”

Catanzara — who may be fired from the police department over offensive social media posts made several years ago — later apologized for making the comparison.

Last Friday, a Cook County judge issued a temporary restraining order against Catanzara that forbade him from publicly urging officers not to get vaccinated.

Just shortly after a judge made that order, Catanzara posted a YouTube video saying officers “need to do what’s in their hearts and minds.” He is then seen in the video holding a sign that says, “John Catanzara for Mayor 2023.”

That restraining order expires Monday, but attorneys for the city asked a Cook County judge to extend it and apply it to other union leaders.

After the city’s Oct. 15 reporting deadline passed, the police department started to meet with officers and other employees — most of whom are assigned to CPD headquarters — who did not disclose their vaccination status.

Higher-ups in the CPD met one-on-one with noncompliant officers, giving them another chance to voluntarily report their vaccine status. If they declined, they were formally ordered to do so. If the order was disobeyed, the officer was placed on no-pay status, sent home and the department lodged a complaint register against the officer.

As of Tuesday, 21 CPD officers refused to comply, but police sources said that number has fluctuated in the days since. Some officers who initially defied the order and were placed on no-pay status later saw their police powers restored after agreeing to the share their vaccination status with the city.

Most city departments saw more than 90% compliance with the city’s vaccine reporting mandate. However, just 67% of CPD employees and 72% of the Chicago Fire Department’s employees shared their vaccination status.

Aside from those with religious or medical exemptions, unvaccinated city employees now have until Dec. 31 to get their shot, though the city has not yet said what the consequences would be for those who fail to comply.