Emanuel's rocky tenure leading Chicago has made him politically toxic among many voters here
, particularly African Americans, and Sanders has worked to push him to the forefront of the Democratic presidential race. Few people are closer to the Clintons than Emanuel, but he has steered clear of the campaign, even as Sanders repeatedly invokes his name at rallies and in television ads.
"I want to thank Rahm Emanuel for not endorsing me. I don't want his endorsement!" Sanders said at a Chicago rally. "I don't want the endorsement of a mayor who is shutting down school after school and firing teachers."
It's an odd piece of political irony that Emanuel could be complicating Clinton's prospects to win the Illinois primary.
His ascension to mayor, with stops along the way as White House chief of staff to President Barack Obama and as an Illinois Congressman, began with his early work on Bill Clinton's presidential campaign. He also famously sparred with First Lady Hillary Clinton more than two decades ago in the White House, which landed him a demotion and nearly got him thrown out of the West Wing.
Emanuel has long ago made amends, but may have to do so again if Clinton doesn't fare well in the primary Tuesday.
At a rally on Monday, a parade of Democrats warmed up the crowd before Clinton arrived at a union hall west of downtown Chicago. Noticeably absent was Emanuel, the city's top-ranking Democrat.
Illinois Sen. Dick Durbin reminded supporters of the importance of the state and the close race with Sanders, saying, "Not a single vote should be taken for granted."
In an interview, Durbin acknowledged that the local political challenges for the mayor have seeped into the presidential race, but he said he expected Clinton to prevail.
"The mayor's going through a rough patch, there's no question about it," Durbin told CNN. "But when it gets right down to it, Hillary and Bill Clinton are well known in Chicago -- in the African-American community and the Latin community."
Durbin, who has served with Sanders in Congress for years, said the decision to draw Emanuel into the race was "within the boundaries of fair campaigning." But he added, "It's a tactical decision on his part, I don't think it's going to work."
But Clinton was taking no chances, sprinting across Chicago to at least four campaign stops with an intensity that felt more like a mayoral race than a national presidential contest. She touched all key Democratic constituencies, visiting a Hispanic immigration center, joining Jesse Jackson at a memorial for children killed in gun violence and meeting with union workers from a Nabisco plant that has sent jobs overseas.
"I know people have been working really hard, but do not rest," Clinton told supporters Monday. "If there is an 'L' stop you can go to, if there is a phone call you can make, if there is a door you can knock on, if there is a person you can convince, please do everything you can in the next 24 hours."
It was an extraordinary amount of time for Clinton to spend in one city -- particularly in her own native backyard -- with five states voting on Tuesday. Her advisers thought they had a narrow advantage heading into the primary on Tuesday, but told supporters that a sweeping victory was critical to "come out of these elections with a wind at our backs."
Sanders, who pledged to run a positive campaign, has increasingly sharpened his tone. His attacks against Emanuel are among his harshest yet, but they just may work. Emanuel recorded a record-low approval rating of 27% in a Chicago Tribune poll in February. His approval was even lower among minority voters, whose support Clinton is counting on in her primary fight with Sanders.
Sanders called a weekend news conference in Chicago with one overarching goal: to forcefully criticize Emanuel and tie him to Clinton.
"Let me be as clear as I can be," Sanders said. "Based on his disastrous record as mayor of Chicago, I do not want Mayor Emanuel's endorsement if I win the Democratic nomination.
The mayor, famously outspoken, has been quiet throughout the presidential campaign. He dismissed Sanders' criticism as he walked in the St. Patrick's Day Parade, telling the Chicago Tribune: "Politics is politics. It's campaign season."
The television advertising campaign Sanders is waging in Chicago is hyper local, featuring critics of Emanuel and his opponent in the 2015 mayoral race,
Jesus "Chuy" Garcia. The ads also feature a teacher highlighting the mayor's decision to close nearly 50 schools in predominantly black and Hispanic neighborhoods.
The mayor's popularity has been shaken by street violence in Chicago and for his part in the Laquan McDonald police shooting case. He has weathered many calls for his resignation -- including from Sanders.
"I think he has done a very bad job," Sanders said, asked if the mayor should resign. "If I lived in this city, I would be active in that effort."
It's an open question whether Sanders can pull off an upset in Illinois. A Chicago Tribune poll last week showed Clinton leading Sanders 67 to 25 percent
. But an NBC/Wall Street Journal/Marist poll
released Sunday showed Clinton with an edge of only six percentage points.
To win Illinois, Clinton needs a strong showing among minority voters in Chicago. Sanders is trying to cut into her advantage, while running strong with white voters across the state.
The Clinton campaign believes Illinois could be the closest of the five states holding primaries on Tuesday, but aides are taking nothing for granted. They dispatched Clinton to Chicago on Monday for a final stop on the eve of the primary, a sign they believe the state is in play.
Sanders is coming back to Chicago, too, a city where he went to college a half-century ago. His campaign decided to add a late rally Monday night, just hours before the voting begins on Tuesday.