In Deck v. Missouri (2005) 544 U.S. 622, a majority of the United States Supreme Court held that "the federal Constitution forbids the use of visible shackles during trial, unless that use is 'justified by an essential state interest'--such as the interest in courtroom security--specific to the defendant on trial." (Id. at p. 624.) California follows similar principles. In People v. Duran (1976) 16 Cal.3d 282, the California Supreme Court reaffirmed the rule that "a defendant cannot be subjected to physical restraints of any kind in the courtroom while in the jury's presence, unless there is a showing of a manifest need for such restraints." (Id. at pp. 290-291.) "Manifest need" arises on a showing of unruliness, an announced intent to escape, or when there is "evidence of any nonconforming conduct or planned nonconforming conduct which disrupts or would disrupt the judicial process if unrestrained . . . ." (Id. at pp. 291-293, fn. 11.) "Even when the record in an individual case establishes that it is appropriate to impose some restraint upon the defendant as a security measure, a trial court properly must authorize the least obtrusive or restrictive restraint that effectively will serve the specified security purposes." (People v. Mar (2002) 28 Cal.4th 1201, 1226; accord Duran, supra, 16 Cal.3d at p. 291.) In People v. Duran (1976) 16 Cal.3d 282, the Supreme Court explained how manifest need should be determined. "In the interest of minimizing the likelihood of courtroom violence or other disruption the trial court is vested, upon a proper showing, with discretion to order the physical restraint most suitable for a particular defendant in view of the attendant circumstances. The showing of nonconforming behavior in support of the court's determination to impose physical restraints must appear as a matter of record and, except where the defendant engages in threatening or violent conduct in the presence of the jurors, must otherwise be made out of the jury's presence. The imposition of physical restraints in the absence of a record showing of violence or a threat of violence or other nonconforming conduct will be deemed to constitute an abuse of discretion." (Duran, supra, 16 Cal.3d at p. 291.) A trial court's determination of the necessity of restraint, when made in accordance with the principles laid down in Duran, "cannot be successfully challenged on review except on a showing of a manifest abuse of discretion." (Id. at p. 293, fn. 12.)