Whether the Fourteenth Amendment's Due Process Clause required Massachusetts to permit Snyder to attend the jury's view of the crime scene after he requested to be present.
Holding
No. Due process requires a defendant's presence only when it bears a reasonably substantial relation to the opportunity to defend; Snyder's exclusion from this particular view did not deny him a fair and just hearing.
Reasoning
The Court began with the limited nature of Fourteenth Amendment due process as then understood. States may structure their own criminal procedures unless they violate a principle of justice so rooted in the nation's traditions and conscience as to be fundamental. Due process unquestionably requires notice of the charge and an adequate opportunity to defend, but it does not constitutionalize every procedure that might be fairer, wiser, or more protective of an accused person.
The Court assumed that, in a felony prosecution, due process protects a defendant's personal presence whenever it has a reasonably substantial relation to the fullness of the defense. This principle can cover stages such as witness examination, jury selection, or argument, where an accused may confront witnesses, advise counsel, or personally participate. But presence is not constitutionally required when it would be useless or would provide only a shadowy benefit.
A bare view of a crime scene does not ordinarily require the defendant's presence. The accused cannot examine the physical scene in the way he can cross-examine a witness, and any concern that jurors viewed the wrong location or that conditions had materially changed can be explored through testimony, photographs, diagrams, or a later inspection with counsel. Snyder had an opportunity to visit the scene afterward and did not identify any discrepancy between the scene viewed and the photographs and diagrams admitted at trial.
The limited statements made at the view did not alter the constitutional result. Massachusetts allowed counsel to point out physical features but not to offer evidence, comment, or argument. The Court treated this as a difference of degree from a silent inspection, consistent with a longstanding historical practice in which persons guiding a jury could identify marks, boundaries, and relevant objects without discussing the merits of the case.
History also supported treating a view as distinct from a trial in court for this purpose. At common law, a judge need not attend a view, and historically even fewer than all jurors could attend one. Those practices showed that a view was not understood as the kind of adversarial courtroom proceeding at which the accused's presence was inherently indispensable. Labels such as 'evidence' or 'trial' could not resolve the constitutional question; the relevant inquiry was whether exclusion, in the circumstances of this record, was flagrantly unfair.
No reasonable possibility of prejudice appeared here. Snyder admitted being at the station during the crime, used the trial diagram to describe the participants' movements, and never claimed that the jury saw an inaccurate or materially altered scene. His counsel attended the view and directed the jurors' attention to defense-favorable features, including the ability to see into the station from outside. In light of the complete record, Snyder's own attendance would not have aided his defense.