What is the burden of proving guilt beyond a reasonable doubt in a collateral review of a final criminal judgment?

[886 P.2d 1270] The majority correctly recognizes that because a judgment is presumed valid, the person challenging its validity bears the burden of proof. (Maj. opn., ante, at p. 265 of 37 Cal.Rptr.2d, at p. 1258 of 886 P.2d) "The initial burden of proving guilt beyond a reasonable doubt is on the prosecution, and the panoply of rights accorded an accused person prior to his conviction supports the presumption that he is innocent. Different considerations apply, however, to collateral review of a final criminal judgment. For purposes of collateral attack, all presumptions favor the truth, accuracy, and fairness of the conviction and sentence; defendant thus must undertake the burden of overturning them. Society's interest in the finality of criminal proceedings so demands, and due process is not thereby offended. [Citations.]." (People v. Gonzalez (1990) 51 Cal.3d 1179, 1260, 275 Cal.Rptr. 729, 800 P.2d 1159, italics in original.)

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