The requirement of a fair trial in criminal proceedings has its constitutional source in the due process clause of the Fifth and FOURTEENTH AMENDMENTS, which declares that no person shall be deprived of "life, liberty, or property, without DUE PROCESS OF LAW." Other provisions of the BILL OF RIGHTS deal explicitly with particular aspects of a criminal trial. Historically, the coverage of those provisions has tended to expand, narrowing the application of the more general provision. The "incorporation" of provisions of the Fifth and SIXTH AMENDMENTS into the due process clause of the Fourteenth Amendment is especially noteworthy in this respect, having had the effect of eliminating the need for fair-trial analysis of issues in state cases covered by those provisions. While important elements of a fair trial are thus treated individually, the requirements can be summarized generally as a hearing before a competent, impartial tribunal, at which the prosecutor does not present the government's case inaccurately or unfairly and the defendant has an opportunity to present his case fully and effectively.
Ordinarily, any judge of a court having JURISDICTION is presumed to be competent to hear a criminal case. However, a judge is presumed not to be impartial if he has a substantial personal interest in a verdict against the defendant. The requirement of a fair trial prohibits a judge from sitting in that circumstance. In Tumey v. Ohio (1927) the Supreme Court held invalid a local practice assigning the mayor of a village as judge in criminal cases, because the compensation for his judicial services and other income for the village accrued only if the defendant were convicted and a fine imposed. In In re Murchison (1955) the Court overturned convictions for criminal contempt following a trial before the same judge who was the defendants' accuser and the principal witness against them.
The Sixth Amendment gives a criminal defendant the right to be tried by an "impartial jury." That provision, which applies to federal and state trials, entitles the defendant to a jury selected from a representative cross-section of the community, without inclusions or exclusions because of sex, nationality, race, or other impermissible classifications. (See JURY DISCRIMINATION.) The jury finally chosen need not have any particular composition or be representative of the community as a whole.
The defendant must have a reasonable opportunity to uncover bias or prejudice of an individual juror. This is afforded by VOIR DIRE, the examination of prospective jurors. The trial judge or the prosecutor and defense counsel question the members of the jury panel to reveal any basis for disqualification in the particular case. The trial judge has broad discretion to direct the conduct and scope of the examination, provided it is adequate to ensure the jurors'
impartiality. Counsel for either side may challenge a juror "for cause" if there is a basis for disqualification and then exercise a limited number of "peremptory" challenges without explanation. In an effort to secure an impartial jury, the prosecutor may, under the DOCTRINE of SWAIN V. ALABAMA (1965), exercise peremptory challenges on the basis of group factors such as race or nationality.
However fair the formal means for ensuring an impartial tribunal, a trial conducted in an atmosphere of mob violence or insistent public pressure for conviction does not meet the...