Three days out from the Illinois primary, Bernie Sanders is diving into local Chicago politics, putting his intense criticism of Mayor Rahm Emanuel at the heart of his pitch.

"Hillary Clinton proudly lists Mayor Rahm Emanuel as one of her leading mayoral endorsers," Sanders said on Saturday. "Well let me be as clear as I can be. Based on his disastrous record as mayor of the city of Chicago, I do not want Mayor Emanuel's endorsement if I win the Democratic nomination."

On Friday night, Sanders expressed the same sentiment at a rally just outside the city, and the crowd of 9,000 erupted in approval. Emanuel, who has fought with public-sector unions in the city and overseen an increasingly controversial police force, has long been unpopular with the progressive voters who comprise Sanders' core support.

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Sanders' campaign has also released three new TV ads in Chicago on Friday, and one of them specifically hits Emanuel, who was once the Chief of Staff for President Barack Obama.

"If you have a presidential candidate that supports someone like our mayor, you have a candidate who is not willing to take on the establishment," Chicago public school principal Troy LaReviere explains in the ad.

Sanders came after Emanuel specifically for his record on education, noting the closing of schools and the firing of teachers in a press conference on Saturday morning. LaReviere was joined at the press conference by a much younger voice: 12-year-old Asean Johnson. Johnson mounted a chair so that he could reach the podium and told the room that he fought against Emanuel in 2013 when he tried to shut down his school.

"Public education is under attack in cities all over America. We need a president that will support and elect a school board. Support equal funding schools, teachers, working class people, humans, families and communities," Johnson said, gesticulating passionately.

Sanders did not call for Emanuel to resign, saying that decision was up to the people of Chicago. He does, however, say that Clinton should reject Emanuel's endorsement. He argued that schools in Chicago have been devastated under the mayor's leadership, insisting that Emanuel "takes on" teachers and schools but fails to take on Wall Street.

"The city of Chicago should sue these banks for fraud and put public pressure on these wealthy bankers to protect Chicago's most precious asset, its children," Sanders explained. "The reality is that there wouldn't be a budget shortfall if Chicago had refused to pay Wall Street banks like Goldman Sachs and Bank of America over $500 million for risky financial schemes that were marketed as a way to finance the public school system."

Emanuel's approval rating in the state hit an all-time low of 27 percent this year, according to a Chicago Tribune poll. One of the major reasons is the alleged cover-up of the police shooting of Laquan McDonald, an unarmed teenager who was shot 16 times by an officer in 2014. A police video of the shooting was of the shooting was released in 2015 and sparked days of protests in the city.

According to that same poll Chicago Tribune poll, 63 percent of African-Americans in the city said that they view Emanuel as untrustworthy. That number may prove to be a problem for Clinton, who has relied on her popularity among black voters to secure wins in a number of Democratic primaries this cycle.

At the press conference, Sanders' African-American backers were asked if they thought Sanders could win over black voters in the city. This prompted of his local supporters and surrogates, 20-year-old Ja'Mal D. Green, to step up to the podium.

"We had these politicians that was funded by these Wall Street corporations do us so bad and take away the resources and opportunities in our neighborhoods, where we don't feel like we want to vote," Green said of black communities in Chicago. He said he is working to get all of his friends out to support Sanders.

"It is the education. If they sit down and look at the platform of Senator Sanders well as Hillary Clinton they will see who is a better candidate," Green said.

Yet not everyone is so sure that the African-Americans will veer away from Clinton, even with Sanders casting himself as the anti-Emanuel.

One 64-year old African-American woman said she was pleased by what she heard from Sanders on Saturday afternoon when he spoke with Jesse Jackson at the Rainbow PUSH Coalition forum on the Southside of Chicago. That said, she was surprised by the small number of folks that showed up to hear the Vermont Senator.

"The African-Americans seem to be more comfortable with the devil they know than with an angel they don't know," she said. "Emanuel is not good but he is the devil they know. I fear it may be the same with Clinton."