An ally of Toni Preckwinkle got into a shouting match with Lori Lightfoot on Monday after Lightfoot accused Preckwinkle of being behind a “power grab” aimed at turning the Cook County’s elected assessor into an appointed office.

State Rep. Robert Martwick (D-Chicago) is a property tax appeals attorney and longtime family friend of former Cook County Assessor Berrios who was a campaign surrogate during Berrios’ failed re-election campaign.

Martwick also happens to be the 38th Ward Democratic committeeman who has endorsed Preckwinkle for mayor.

On Friday, Martwick filed a bill in Springfield that would dramatically change the way Cook County assessor is chosen.

Starting in 2022, after newly-elected assessor Fritz Kaegi completes his first term, the assessor would be appointed by the county board president and confirmed by the Cook County board.

On Monday, Lightfoot held a news conference to accuse Martwick of filing that bill on Preckwinkle’s behalf as part of a “power play” aimed at “undermining” Kaegi as he seeks to reform a “broken property tax system” that’s “pushing black and brown families out of Chicago.”

But no sooner had she left the podium then up stepped Martwick to crash the party and get right in Lightfoot’s face.

“This sort of Trump-style where you’re trying to draw attention to yourself without assessing the facts of the situation shows exactly why you are wholly unprepared to be the mayor of this city,” Martwick said.

Lightfoot stood her ground.

“You were a Joe Berrios surrogate for the entire campaign. You filed this bill to profit yourself. Who benefits from a system that’s not changed?” Lightfoot said.

Martwick countered, “Oh please. That’s ridiculous. This is beneath you . . . There are legitimate things that we can do to reform the political process around assessments. But you don’t want to have that conversation.”

Lightfoot was not appeased by the delayed implementation date or by the fact that Martwick called Kaegi to give him a heads-up three hours after filing the bill.

She called the bill an obvious attempt to “undermine” Kaegi as he seeks to repair a broken assessment system and “reclaim power for themselves.”

“It’s not gonna take one term to fix the system. And to allow the Cook County board president to pick a crony” is outrageous, she told Martwick.

“Why wouldn’t Fritz Kaegi run for re-election if he does a good job? Why not let the voters decide instead?”

With Lightfoot still in his grill, Martwick said, “I assume at some point, he’s gonna move on. I assume at some point, he’s not gonna be the assessor . . . Do you know how many assessing jurisdictions have appointed vs. electing assessors?”

Lightfoot parried: “What I know is that we have a broken and corrupt system that you were super happy to protect because of your allegiance to Joe Berrios.”

With Martwick continuing to shout over her, Lightfoot said, “This is Rob Martwick, Exhibit ‘A’ of the broken and corrupt political system.”

Lightfoot thanked him for showing up, prompting Martwick to say sarcastically, “Happy to do it. Happy to answer questions about legislation that is designed to provide reform and to begin a discussion.”

When Lightfoot finally left the room, Martwick insisted that he filed the bill only as a conversation starter. He insisted that he had no intention of moving the legislation. Nor was he put up to it or Monday’s public debate by Preckwinkle.

Preckwinkle’s office tweeted out a joint statement with Kaegi, saying the assessor’s office should remain an elected position. Preckwinkle also tweeted that she has had “no conversations” with Martwick about the bill and that it would “mean more politics in county government, not less.”

Martwick said he got a text from the Preckwinkle campaign alerting him to Lightfoot’s news conference — but was already in the room when the alert arrived.

“It would be one thing if I didn’t have a history of doing this,” Martwick had said earlier Monday. “I come with the experience and expertise I have. Who else is going to propose legislation like this? To assign a malintent to it is unfortunate because this is about restoring integrity to taxpayers. Berrios is gone, his political career is done. To talk about him . . . that’s old news.”

Kaegi’s office issued a statement Monday in response to Martwick’s bill:

“The Cook County assessor should be an elected position so that it remains accountable to the people who pay our county’s property taxes,” the statement read. “Assessor Kaegi made promises of ethics, accountability and fairness for this office and while we’re proud of the work we’ve done in the last two months to reform this system, we did just take office in December so right now we’re focused on our work, not politics.”

It’s not the first time Lightfoot has made an issue of Preckwinkle’s longstanding alliance with Berrios, Preckwinkle’s predecessor as chairman of the Cook County Regular Democratic Organization.

In early October, Lightfoot lambasted Preckwinkle for honoring Berrios at the party’s annual fundraiser.

At the time, Jacob Kaplan, executive director of the Cook County Regular Democratic Organization, made no apologies for the decision to honor Berrios, made by the party’s executive board.

“During his time here, the party endorsed many more minority candidates, women candidates. His record at the party level speaks for itself in terms of what he did to open up the party to more diversity and things like that. That’s the reason he’s being honored,” Kaplan said.

Asked about the assessment controversy, Kaplan said, “This is just about the party. It’s about his party leadership.”

Retired Chicago Teachers Union President Karen Lewis and retired Illinois Supreme Court Justice Charles Freeman were honored along with Berrios.

Contributing: Rachel Hinton