The City Council is poised to vote Wednesday on two parts of Mayor Rahm Emanuel’s police accountability overhaul, with a promise to add the critical “third leg” — a civilian oversight board — in short order.

Without a civilian panel charged with choosing a permanent chief for the Civilian Office of Police Accountability, the agency that will replace the discredited and soon-to-be-abolished Independent Police Review Authority, aldermen warned that public trust shattered by the mayor’s handling of the Laquan McDonald shooting video will never be restored.

To reassure them, the mayor plans to introduce a resolution Wednesday reaffirming his commitment to put that final piece of the puzzle in place during the first quarter of 2017.

“This is not a punt or a stall,” Corporation Counsel Steve Patton assured the Committees on Budget and Public Safety during a marathon meeting Tuesday on the mayor’s plan to replace IPRA with COPA and create a new deputy inspector general for public safety.

On Tuesday evening, COPA passed out of the committee on a 21-4 vote. That sets the stage for Wednesday’s final showdown in the full Council.

“The reason for the delay isn’t because any of you asked for it or because the mayor asked for it. It’s because community groups — more than a dozen of them — came to us . . . and said, `It’s too critical we get it right. We urge you to stay put until we have a chance for further engagement.’ Out of deference to that request, we’ve done that,” Patton said.

He reminded aldermen that the mayor’s ordinance is the painstaking product of nine public hearings, countless meetings with stakeholders and a ton of rewrites to address the three biggest complaints about COPA: a guaranteed budget, authority to hire independent counsel and a five-year ban on former police officers serving as investigators.

The corporation counsel further argued that time is of the essence because IPRA is “hemorrhaging” investigators, adding, “We are very close to a crisis point.”

Ald. Chris Taliaferro (29th), a former Chicago Police Officer, didn’t buy it. He urged his colleagues to wait on the third leg of the triangle instead of “rushing through a two-pronged ordinance” that will do nothing to fill the “gap of trust” between citizens and police.

“Any stool with just two legs” won’t stand up, Taliaferro said.

Ald. Leslie Hairston (5th), whose rival police accountability ordinance is still pending, argued that the mayor’s office “retains control” in Emanuel’s version and that the corporation counsel’s office has not “erased its conflict of interest.”

“A top-down approach won’t repair the broken relationship” between citizens and police, she said.

Tuesday’s joint committee meeting dragged on for so long, most of those who signed up to testify about the mayor’s ordinance had already left the City Council chambers by the time their names were called.

​At one point, Budget Committee Chairman Carrie Austin (34th) ordered Chicago Police officers to remove an angry protester shouting​ obscenities at aldermen.

Police Board President Lori Lightfoot co-chaired the mayor’s Task Force on Police Accountability, which characterized IPRA as so “badly broken” it needs to be abolished.

She agreed with aldermen that “The violence numbers that we see will not go down until there is a better relationship with the police. It’s common sense to me that reform and accountability and policing efficiency and effectiveness go hand-in-hand.”

But Lightfoot warned that finding the appropriate method for choosing the all-important civilian review board members will not be an easy task.

The mayor’s resolution does not answer the pivotal questions that will determine just how independent that civilian board will be.

How will those civilian representatives will be chosen? How many members will there be? Will Emanuel insist on controlling a majority?

Critics have warned that a panel controlled by the mayor would have no credibility with the public.

“There’s been a lot of organized effort around the notion of having an elected board. I personally do not favor that,” Lightfoot said.

“If you don’t have enough resources and you don’t have money to run a campaign to go door-to-door to reach people in their homes, then you have a small group of monied interests that have the potential to control the elections and therefore control the policymaking of the board,” she said.

The mayor’s ordinance gives COPA a guaranteed budget of 1 percent of the Chicago Police Department’s budget, not including grant funding.

That’s roughly $14 million or $2.1 million more than an IPRA budget the police reform advocates have called so totally inadequate it virtually guarantees that investigations of police wrongdoing will drag on for months or even years.

The increased budget is particularly important, considering the fact that COPA will inherit an expanded annual caseload that, under the mayor’s ordinance, will include false arrests, illegal searches, denials of counsel and other constitutional complaints.

Also in line for a guaranteed budget is the new deputy inspector general for public safety charged with auditing police practices, identifying troubling trends, recommending changes to the police contract and bird-dogging the new multi-tiered accountability system.

Instead of requiring Inspector General Joe Ferguson to add those formidable responsibilities to his already crowded plate without any additional funding beyond the one-tenth of 1 percent of the overall city budget he already receives, Ferguson’s budget would be increased to .14 percent to roughly $8.4 million. That’s up $2.4 million from the inspector general’s current budget.

COPA will have authority to “retain counsel to enforce and defend against subpoenas and to advise and represent the office with respect to its investigations.”

Outside counsel would be chosen “from a pool of no fewer than five firms previously approved by the corporation counsel after consultation with” COPA, the amendment states.

Current or former Chicago Police officers would be prohibited from serving as COPA investigators for at least five years.