The Hollywood star's presence, and the accompanying media hubbub, is bound to affect the proceedings, which begin Monday. That's when presiding Judge Charles Burns plans to start questioning would-be jurors one by one, trying to weed out anyone who could be swayed by Hudson's celebrity status.
Hudson is expected to be at the trial every day once testimony begins, court officials say, and she's on the 300-name list of witnesses who could testify. While the judge will warn prospective jurors to avoid watching TV coverage of the trial, they may see Hudson on "American Idol" on Thursday.
Legal experts widely agree on the No. 1 challenge at trials involving megastars: It's identifying 12 jurors able and willing to assess guilt solely on what they hear in court.
Hudson will need to refrain from overt displays of emotion as potentially starstruck jurors' eyes dart back at her, said Gerald Uelmen, a defense attorney at O.J. Simpson's murder trial.
"The risk is that jurors may be watching her rather than testifying witnesses, and they could be influenced by how she reacts," he said. "She would be well advised not to engage in any facial expressions or outbursts. That could be grounds for a mistrial."
Prosecutors say William Balfour, the 30-year-old estranged husband of Hudson's sister, shot the family in a jealous rage because Julia Hudson was dating another man. Jennifer Hudson, also 30, and Balfour grew up in the same South Side neighborhood.
The bodies of Hudson's mother, Darnell Donerson, 57, and brother, Jason Hudson, 29, were found shot to death in the family's home on Oct. 24, 2008. The body of her nephew, Julian King, was found days later in a vehicle several miles away.
Balfour's attorneys have said the evidence is circumstantial, though prosecutors say proof he committed the crime will include gun residue found on his car's steering wheel.
Adored by many Chicagoans, Hudson will pose a stark contrast to Balfour, a short man with a long criminal record. He was a one-time Gangster Disciples gang member and known by his street name, "Flex," according to court documents.
The dilemma posed by Balfour's trial became clear last week, when 150 potential jurors filled out their questionnaires in court. Nine of the 66 questions dealt with Hudson's career: Would-be jurors were asked if they'd ever seen her Academy Award-winning film "Dreamgirls" and if they belong to an organization for which Hudson is a spokesperson, presumably a reference to Weight Watchers.
It was obvious many potential jurors had heard of the killings, some gasping when the judge first read the name of the case.
And when Burns asked if anyone felt they couldn't hear the evidence "without sympathy, bias or prejudice" to step up, he looked on with apparent alarm as five, 15, then 20 people rose. He finally told everyone to sit down and disregard the question, for now.
The history of high-profile trials—from Simpson's to Michael Jackson's doctor, Conrad Murray—suggests it's hard to dim the celebrity glow. But Burns, known as a competent but quick-tempered judge, wants to ensure the buzz doesn't undercut Balfour's right to a fair trial. He's made it clear he won't tolerate disruptions. He's barred tweeting from inside court because he fears feverish typing would distract jurors. He's imposed gag orders on attorneys.
Cameras also won't be allowed in the courtroom, though that won't stop the media circus outside. Chicago isn't a paparazzi hot spot, but cameramen are likely to swoop in from New York or Los Angeles, said Ray Murray, an associate journalism professor at Oklahoma State University who studies paparazzi.
"Going in and out of the courtroom won't be fun for her," Murray said. "They look like cannons, some of these cameras, and if you're going through what she's about to go through, you can imagine that would rattle her."
The brush with celebrity may be irresistible for jurors, as there's a tendency to feel a protective bond with movie stars and singers almost as if they're family, said prominent defense lawyer Gerry Spence.
There could be "a sort of underlying sense, a subconscious sense, that they have attacked somebody in (the juror's) family," said Spence. "And they think, '(He) shot Jennifer's (mother, brother and nephew) and I'm going to get him.' "
The defense could ask Burns to bar Hudson from court—possibly on grounds she is a potential witness—which would be a rare but not unheard of request. But Uelmen says the judge would be reluctant to tell a daughter she can't attend the trial of the man accused of killing her mother.
Hudson's publicity firm did not respond to requests for comment.
Judges don't insist jurors be blank slates, they merely want to know if jurors can set aside their biases and preconceptions, said Laurie Levenson, a law professor at Loyola Law School Los Angeles.
"You certainly don't want a juror who hasn't heard of Jennifer Hudson, for instance," Levenson said. "That would raise other serious questions, like, where's this person been living—under a rock?"
Attorneys won't necessarily share the judge's goal of weeding out bias.
"The fact is," Uelmen said, "neither side is looking for unbiased jurors—they're looking for jurors who lean their way."
AP reporter Don Babwin contributed to this report.
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