Five reasons why Clinton won, but narrowly
Democrat Hillary Clinton won her native state by a slim margin Tuesday over Vermont Sen. Bernie Sanders, a self-described democratic socialist who almost pulled an upset here.
Here's why it happened:
Home team
Clinton has roots in Illinois, where she was born in Chicago and raised in Park Ridge. She's often talked about her mother in the campaign, hearkening back to her time in the suburbs.
"We liked our parents. We liked our friends. We liked where we lived. There was not a bunch of angst," Clinton childhood friend Betsy Ebeling of Arlington Heights said earlier this year.
Clinton was defeated here in 2008 by President Barack Obama, who grabbed the home-state mantle that time. This time, she won her state, but barely.
Rahm Emanuel
The Chicago mayor might be one reason Sanders got so close to an upset.
At a time when candidates often seek out the support of local notables in their quests for votes, Sanders took a hard line on Emanuel.
"Let me be as clear as I can be," Sanders said at a rally over the weekend. "Based on his disastrous record as mayor of the city of Chicago, I do not want Mayor Emanuel's endorsement."
Emanuel election opponent Jesus "Chuy" Garcia gave a rousing speech at Sanders' final Illinois rally Monday and many of the faithful supporters standing in line to get in mentioned Emanuel as a reason they backed Sanders.
Big names
Even before any votes were counted here, it was clear Clinton would net more Illinois delegates than Sanders because of the cadre of party leaders supporting her.
Clinton earned commitments from most of the Chicago area's so-called superdelegates, Democrats who get to make up their own minds about how to vote at the summer political conventions.
Their support was on display at Clinton's last rally at a Chicago union hall, where she was introduced by popular Democrats Sen. Dick Durbin and Illinois Attorney General Lisa Madigan.
Cook County
Illinois' biggest county, and one of the top Democratic strongholds in the country, went for Clinton.
In Chicago where she was born, Clinton got more than 53 percent of the vote in late unofficial returns. And in suburban Cook County where she grew up, Clinton tallied about the same percentage.
Big wins there meant Sanders had to make up ground elsewhere. And while he won a lot of counties downstate, there weren't enough voters among them to put him over the top.
The "Bern"
Sanders came within a percentage point or two of beating Clinton in a year when the political establishment is facing heavy criticism from both parties.
On the Democratic side, Sanders has made campaign finance one of his keystone issues, hitting Clinton for a campaign bankrolled in part by political action committees.
The idea that the candidate can't be bought was a winning issue for Illinois' Republican victor, too, Donald Trump.