Types of Challenges.
Parties may bring two types of challenges against potential jurors: for cause and peremptory. With the former, parties seek to strike jurors based on perceived bias or partiality. Depending on the jurisdiction, a judge or an independent “trier” will make the ultimate determination of whether to strike the juror. With the latter, parties may strike jurors without offering any reason.
Number of Challenges.
Each party receives an unlimited number of challenges for cause. By contrast, the number of available peremptory challenges is limited. The exact number varies from court to court: In the federal system, each side receives three such challenges. See 28 U.S.C. § 1870. In state courts of general jurisdiction, the number ranges from two (in a handful of states) to eight (in North Carolina). See Bureau of Justice Statistics, State Court Organization 2004 tbl. 41.
Social Science Research.
Often, attorneys will seek to empanel jurors who will identify with their clients. Over the past several decades—in part in response to this practice—social science research has attempted to gauge the extent to which jurors’ personality traits or demographic characteristics will influence their interaction with other jurors and the likelihood of a particular outcome. See generally Dennis J. Devine et al., Jury Decision Making: 45 Years of Empirical Research on Delibarating Groups, 7 Psychol. Pub. Pol'y & L. 622 (2001).
The following cases consider the limits to these two types of challenges.