The expansion of mass media has led to an explosion in news coverage of criminal activities to the point where it has become virtually impossible to find citizens who are unaware of the details of crimes committed in their communities. Since it is generally believed that people who know the facts of a case are more likely than those who do not to hold an opinion about the case, and that it is more desirable to empanel jurors who do not need to set aside personal prejudices in order to render a verdict, empaneling impartial juries has proven to be a daunting task in North American courts, particularly in trials involving issues or people of public interest.

Judges rely on several techniques to minimize partiality in the courtroom, including moving trials to new venues and giving specific instructions to juries. While many judges are convinced that these techniques work, many critics have concluded that they are ineffective. Change of venue, the critics argue, cannot shield potential jurors from pretrial publicity in widely reported cases. Nor, they claim, can judges' instructions to juries to ignore information learned outside the courtroom be relied upon; one critic characterizes such instruction as requiring of jurors "mental contortions which are beyond anyone's power to execute."

The remedy for partiality most favored by judges is voir dire, the questioning of potential jurors to determine whether they can be impartial. But critics charge that this method, too, is unreliable for a number of reasons. Some potential jurors, they argue, do not speak out during voir dire (French for "to speak the truth") because they are afraid to admit their prejudices, while others confess untruthfully to having prejudices as a way of avoiding jury duty. Moreover, some potential jurors underestimate their own knowledge, claiming ignorance of a case when they have read about it in newspapers or discussed it with friends. Finally, the critics argue, judges sometimes phrase questions in ways that indicate a desired response, and potential jurors simply answer accordingly.

These criticisms have been taken seriously enough by some countries that rely on juries, such as Canada and Great Britain, that they have abandoned voir dire except in unusual circumstances. But merely eliminating existing judicial remedies like voir dire does not really provide a solution to the problem of impartiality. It merely recognizes that the mass media have made total ignorance of criminal cases among jurors a virtual impossibility. But if a jury is to be truly impartial, it must be composed of informed citizens representative of the community's collective experience; today, this experience includes exposure to mass media. Impartiality does not reside in the mind of any one juror; it instead results from a process of deliberation among the many members of a panel of informed, curious, and even opinionated people.