What is the burden of proving beyond a reasonable doubt against a defendant in a sexual assault case?

The due process clause precludes a conviction unless the state has proved beyond a reasonable doubt every fact necessary to constitute the crime with which the accused is charged. (Patterson v. New York (1977) 432 U.S. 197, 204.) This burden cannot be shifted to a defendant. (Id. at p. 205.) Thus, "the Due Process Clause requires the prosecution to prove beyond a reasonable doubt all of the elements included in the definition of the offense of which the defendant is charged." (Id. at p. 210.)