Whether trial judges must define 'reasonable doubt' for the jury upon the defendant's request

The Fifth and Sixth Amendments protect “the accused against conviction except upon proof beyond a reasonable doubt.” In re Winship , 397 U.S. 358, 364 (1970); Sullivan v. Louisiana , 508 U.S. 275, 277–278 (1993). This standard governs criminal cases in every jurisdiction across the country. But courts are deeply split over whether, upon a defendant’s request, trial courts must explain to the jury what the reasonabledoubt standard means. At least ten jurisdictions require trial courts to define reasonable doubt, at least five jurisdictions prohibit trial courts from defining the term, and at least twenty-three jurisdictions have adopted a position in between. The question presented is: Whether trial judges must define “reasonable doubt” for the jury upon the defendant’s request.