Full context:   In 1898 the Supreme Court held that the jury must be composed of at least twelve persons, although this was not necessarily extended to state civil jury trials. In 1970, however, the Supreme Court held that the twelve person requirement was a "historical accident", and upheld six-person juries if provided for under state law in both criminal and civil state court cases. There is controversy over smaller juries, with proponents arguing that they are more efficient and opponents arguing that they lead to fluctuating verdicts. In a later case, however, the court rejected the use of five-person juries in criminal cases. Juries go through a selection process called voir dire in which the lawyers question the jurors and then make "challenges for cause" and "peremptory challenges" to remove jurors. Traditionally the removal of jurors based on a peremptory challenge required no justification or explanation, but the tradition has been changed by the Supreme Court where the reason for the peremptory challenge was the race of the potential juror. Since the 1970s "scientific jury selection" has become popular.