Karen Lewis and the Chicago Teachers Union on Wednesday asked for the resignation of Mayor Rahm Emanuel and Cook County State's Attorney Anita Alvarez. View Full Caption Getty;DNAinfo

CHICAGO — The Chicago Teachers Union has officially asked Mayor Rahm Emanuel to resign, a move that widens the rift between teachers and Emanuel as he deals with the fallout over the Laquan McDonald case and faces a possible teachers strike.

Members of the union's governing body voted Wednesday to pass a resolution seeking the removal of Emanuel and State's Attorney Anita Alvarez, the union said in a news release Thursday. Union President Karen Lewis will discuss the vote and the union's position on Emanuel and Alvarez at the "peace breakfast" the union will be holding Friday in honor of Martin Luther King Jr.

The resolution says that Emanuel and Alvarez "impeded" the criminal justice system in working to keep the video of McDonald's death from public view while only bringing charges against the teen's killer once the video was released.

The group said it would work to support a state bill that would allow for a recall vote for Emanuel.

"Both ... Alvarez and Mayor Rahm Emanuel orchestrated and intentionally delayed the release of these videos apparently for their own political gains in order to secure victory in their 2015 re-election bids," the resolution reads.

The union's stance on Emanuel will not surprise many. Lewis and Emanuel battled very publicly during the teacher's strike of 2012, and the union worked hard to elect Emanuel's opponent in last year's election, Chuy Garcia.

In December, union members voted to authorize a strike should the union's bargaining team deem it necessary after another round of contract talks stalled. The earliest that strike could happen is March, they said.

Union members have been vocal participants in the public demonstrations against Emanuel and Alvarez. Lewis asked her members to march on the Magnificent Mile on Black Friday, though Lewis herself did not show up.

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