Earline Martin (D) and her husband, Walter argued over grocery money. D claimed that her husband struck her in the head during the argument. D's version of what then transpired was that she went upstairs, put on a robe, and later came back down with her husband's gun which she intended to dispose of. Her husband saw something in her hand and questioned her about it. He came at her, and she lost her head and fired the gun at him. Five or six shots were fired, three of them striking and killing Mr. Martin. D was charged with and tried for aggravated murder. D pleaded self-defense and testified in her own defense. The judge charged the jury with respect to the elements of the crime and of self-defense and rejected Dr's Due Process Clause challenge to the charge placing on her the burden of proving self-defense. The jury found her guilty. The Ohio Court of Appeals and the Supreme Court of Ohio affirmed the conviction. Both rejected the constitutional challenge to the instruction requiring petitioner to prove self-defense. It concluded that P was required to prove the three elements of aggravated murder, but P did not have to disprove self-defense, which is a separate issue that did not require D to disprove any element of the offense with which she was charged. P proved beyond a reasonable doubt that D purposely, and with prior calculation and design, caused the death of her husband. The Supreme Court granted certiorari.