It may seem like the union for Chicago’s 12,000 rank-and-file officers could not possibly become more conservative and combative, but balloting that ends Thursday afternoon could lead to an election showdown between two cops intent on proving it can.

John Catanzara, one of five candidates for president of the Fraternal Order of Police’s Lodge 7, made headlines in 2017 by posting a photo of himself on Facebook dressed in his police uniform and holding a U.S. flag and a hand-lettered placard: “I stand for the anthem. I love the American flag. I support my president and the Second Amendment.”

Another candidate, Martin Preib, writes books and blog posts labeling the wrongful conviction movement a “cottage industry” in which civil-rights attorneys make fortunes off taxpayers by filing lawsuits for murderers who should never have been released from prison.

Catanzara and Preib are arguably the race’s frontrunners, having assembled the largest and most influential slates of candidates for FOP leadership posts.

Preib’s “The Right Choice” slate includes 11 of the lodge’s 27 current elected officers. Catanzara’s slate, “2020 Vision Team,” includes 10. Kevin Graham, the lodge’s current president, heads “True Blue,” a slate with just 4 current officers.

The election tally on Thursday could pit Preib against Catanzara unless one candidate wins more than 50% of the vote.

Catanzara on Wednesday told WBEZ he is running partly to send a message to Mayor Lori Lightfoot: “If you want to work together, we’re willing to sit down and talk. But if you want to continue fighting us, my team and Lodge 7 will bring a fight like no other FOP has before — to any mayor ever.”

Lightfoot’s office did not respond to requests for comment.

Catanzara said his top aim is “restoring faith and pride in being a Lodge 7 member by actually standing up for the members consistently, being the voice they have sought for a very long time, especially in these anti-police days.”

CPD says it stripped Catanzara of police powers in October 2019. That disciplinary case, according to the officer, stemmed from filing a police report against now-fired Police Supt. Eddie Johnson after the top cop marched arm-in-arm with Rev. Michael Pfleger on the Dan Ryan Expressway during a 2018 protest against gun violence.

“I am different than any candidate, now or in the past,” Catanzara said. “I am unafraid of speaking my mind. I have taken every form of retaliation the Police Department can throw at a member and I am still standing. I can walk away and retire tomorrow morning. My only reason for staying at this point is to fight this fight on behalf of the members.”

The other priorities, Catanzara said, would be winning a “fair” contract for cops and waging a court battle to overturn a Chicago residency requirement for the police.

Catanzara’s criticism of his rivals includes a Facebook slam about a Graham and Preib letter urging Trump to free imprisoned former Governor Rod Blagojevich: “These guys are actually bragging about supporting a crooked politician for early release but saying they are going to hold politicians like [Cook County State’s Attorney Kim] Foxx accountable. They have zero credibility now!”

Preib, currently the FOP’s second vice president, helped orchestrate Graham’s 2017 election.

Preib’s official campaign biography says he has many qualifications for the union’s top job. It praises his work ethic and says he has “spearheaded campaigns against” an Illinois commission set up nearly a decade ago to hear claims of alleged torture by officers under the late CPD Cmdr. Jon Burge.

The biography also says Preib has pushed for legislation making it more difficult for “falsely exonerated criminals to file bogus lawsuits against arresting police officers” and that he has waged “high-profile attacks” on Foxx.

Preib declined to comment on his FOP candidacy.

Graham, who also declined to comment, was the only local official to greet Donald Trump on the airport tarmac when the president visited Chicago in October.

Graham unseated President Dean Angelo Sr. as police faced a gun-violence surge and widespread hostility after the release of a video showing teenager Laquan McDonald’s fatal shooting by Police Officer Jason Van Dyke.

Graham promised to confront the “anti-police movement” and to resist any weakening of protections from discipline in the FOP’s contract, which was about to expire.

Nearly three years later, the FOP still lacks a contract. In December, the union’s board voted to put its demand for an 18% pay raise over three years in the hands of an independent arbitrator.

The election ballots went in the mail last month. The FOP says the votes will be counted Thursday afternoon.

The other candidates are Michael Seiser and Ray Casiano, who served as the lodge’s first vice president under Angelo. Neither responded to requests for comment.