When it's up to 12 random people to decide the fate of a defendant in a high-profile court case that has caught the eyes and ears of the nation, judges want to seat the fairest jury possible.

But in big, high-profile cases, just how practical is it to expect to get a 100 percent impartial jury?

"You're talking about fair, you're not talking about ignorant of the fact," said Fox News senior judicial analyst Andrew Napolitano. "You're not looking for a perfect juror, you're not looking for the Holy Ghost, you're looking for a fair person."

Several significant criminal cases in recent months have received tremendous coverage on TV, in print and on the Web. Among them:

-- Scott Peterson (search) faces trial for double homicide in the killing of his wife, Laci, and their unborn son, Conner.

-- Kobe Bryant (search), the Los Angeles Lakers basketball star, will be tried for the sexual assault of a female worker at a Colorado resort.

-- John Allen Muhammad (search) and Lee Boyd Malvo (search ), the two men accused in the D.C. sniper spree last year, could face several trials.

Muhammad is the first to face a jury, which was chosen last week in Virginia Beach, Va. The 42-year-old is charged in the slaying of Dean Harold Meyers, a 53-year-old Vietnam veteran who was gunned down outside a northern Virginia gas station last October. In all, Muhammad and Malvo are charged with 13 shootings, including 10 deaths, in Virginia, Maryland and Washington, D.C.

During jury selection in Muhammad's trial, a schoolteacher was eliminated after saying "it would be very hard" to set aside the fear she and her friends who lived in Washington felt during the shooting spree. Yet defense lawyers unsuccessfully tried to get rid of another juror who said he believed in the principle of an "eye for an eye."

Dr. Robert Gordon, director of the Wilmington Institute of Trial and Settlement Sciences in Dallas, said if a "fair and impartial" juror is defined as someone with no preconceived opinions, impressions or beliefs concerning the case, "you can never seat a fair and impartial jury in a high-profile case."

But if the court is looking for thoughtful people who haven't yet made a final conclusion of guilt or innocence and are willing to set aside their opinions to make a fair ruling, then "absolutely, you can seat a fair and impartial jury," he said.

'Slow, Painstaking, Methodical Process'

To ensure impartiality, the judge often picks 100 or more people, interrogates them and narrows the field down to a smaller group of potential jurors. Then, prosecutors and defense lawyers take turns questioning the group and pick the final 12.

"It is a slow, painstaking, methodical process with the judge … sitting in front of the juror, looking at them eye to eye, trying to decide if they're a fair person," Napolitano said.

Jurors are asked questions such as: "If you were the defendant, would you want yourself on the jury?" and "If your brother was on trial for this crime, would you want to serve on this jury?"

In the Bryant case, Gordon said, lawyers may ask how the jurors feel about black people or sports figures.

Some attorneys often seek a change of venue to boost chances a jury will be less affected by the case.

"The hardest one to get an impartial jury for is in Kobe Bryant's case … it's in a small community," said John Wesley Hall, secretary of the National Association of Criminal Defense Lawyers. "The D.C. sniper case was on television constantly for so long … Kobe Bryant, the case just keeps getting stirred up."

But in cases like Bryant's, a change of venue probably won't help because of the media attention.

"It's sort of like Timothy McVeigh or the [D.C.] sniper trial -- you cannot go to a venue where people aren't aware of it," Gordon said, referring to the man convicted for planning and setting the 1995 Oklahoma City bombing (search) that killed 168 people.

"So the question is, will people be able to postpone the ultimate decision until they've heard all the evidence and play the role of a juror and be fair?" Gordon said. "Most adults can do that … the challenge is, do they [others] know they can't do it?"

But it's virtually impossible to find jurors who know nothing about such cases, most legal experts said.

"It doesn't matter if you've just heard one thing -- that Kobe Bryant raped a woman -- or if you listened to all the garbage that followed," Gordon said. "The real issue is, have you formed an opinion about that?"

Then, there's always the chance that jurors will feign they know little about the case to ensure a seat on a high-profile case.

"You run the risk of jurors lying about what they really know, just because they want to be on the jury," Hall said. But "in a case like O.J. Simpson, where they [jurors] were sequestered for so damn long, that could be a real pain. They don't want to be on a jury if it means being sequestered forever."

Then there's the issue of the 24-hour media cycle and how much that affects juries' impartiality. The O.J. Simpson murder trial, where cameras were allowed in the courtroom, renewed the age-old debate over whether the constitutional rights to a free press can be balanced with a fair trial. (The former football star and occasional actor was acquitted in 1995 for the double murder of his wife and another man).

"We live in a world where our trials are on television and in the media," Gordon said. "Maybe that's good and maybe that's bad."

Even with the constant news cycle, however, it's still possible to get fair jurors, Hall said.

"Just because it's been in the press doesn't mean everybody's actually aware of what happened."