The distinction comports with fundamental legal principles of causation and intent. First, when a patient refuses life- sustaining medical treatment, he dies from an underlying fatal disease or pathology; but if a patient ingests lethal medication prescribed by a physician, he is killed by that medication. See, e.g., People v. Kevorkian, 447 Mich. 436, 470- 472, 527 N.W.2d 714, 728 (1994), cert. denied, 514 U.S. 1083, 115 S.Ct. 1795, 131 L.Ed.2d 723 (1995); Matter of Conroy, 98 N.J. 321, 355, 486 A.2d 1209, 1226 (1985) (when feeding tube is removed, death “result[s]... from [the patient’s] underlying medical condition”); In re Colyer, 99 Wash.2d 114, 123, 660 P.2d 738, 743 (1983) (“[D]eath which occurs after the removal of life sustaining systems is from natural causes”); American Medical Association, Council on Ethical and Judicial Affairs, Physician- Assisted Suicide, 10 Issues in Law & Medicine 91, 92 (1994) (“When a life-sustaining treatment is declined, the patient dies primarily because of an underlying disease”).

Furthermore, a physician who withdraws, or honors a patient’s refusal to begin life-sustaining medical treatment purposefully intends, or may so intend, only to respect his patient’s wishes and “to cease doing useless and futile or degrading things to the patient when [the patient] no longer stands to benefit from them.” Assisted Suicide in the United States, Hearing before the Subcommittee on the Constitution of the House Committee on the Judiciary, 104th Cong., 2d Sess., 368 (1996) (testimony of Dr. Leon R. Kass). The same is true when a doctor provides aggressive palliative care; in some cases, pain- killing drugs may hasten a patient’s death, but the physician’s purpose and intent is, or may be, *2299 only to ease his patient’s pain. A doctor who assists a suicide, however, “must, necessarily and indubitably, intend primarily that the patient be made dead.” Id., at 367. Similarly, a patient who commits suicide with a doctor’s aid necessarily has the specific intent to end his or her own life, while a patient who refuses or discontinues treatment might not. See, e.g., Matter of Conroy, supra, at 351, 486 A.2d, at 1224 (patients who refuse life- sustaining treatment “may not harbor a specific intent to die” and may instead “fervently wish to live, but to do so free of unwanted medical technology, surgery, or drugs”); Superintendent of Belchertown State School v. Saikewicz, 373 Mass. 728, 743, n. 11, 370 N.E.2d 417, 426, n. 11 (1977) (“[I]n refusing treatment the patient may not have the specific intent to die”).

The law has long used actors’ intent or purpose to distinguish between two acts that may have the same result. See, e.g., United States v. Bailey, 444 U.S. 394, 403-406, 100 S.Ct. 624, 631-633, 62 L.Ed.2d 575 (1980) (“[T]he ... common law of homicide often distinguishes ... between a person who knows that another person will be killed as the result of his conduct and a person who acts with the specific purpose of taking another’s life”); Morissette v. United States, 342 U.S. 246, 250, 72 S.Ct. 240, 243, 96 L.Ed. 288 (1952) (distinctions based on intent are “universal and persistent in mature systems of law”); M. Hale, 1 Pleas of the Crown 412 (1847) (“If A., with an intent to prevent gangrene beginning in his hand doth without any advice cut off his hand, by which he dies, he is not thereby felo de se for tho it was a voluntary act, yet it was not with an intent to kill himself”). Put differently, the law distinguishes actions taken “because of” a given end from actions taken “in spite of” their unintended but foreseen consequences. Feeney, 442 U.S., at 279, 99 S.Ct., at 2296; Compassion in Dying v. Washington, 79 F.3d 790, 858 (C.A.9 1996) (Kleinfeld, J., dissenting) (“When General Eisenhower ordered American soldiers onto the beaches of Normandy, he knew that he was sending many American soldiers to certain death.... His purpose, though, was to ... liberate Europe from the Nazis”). [Vacco v. Quill at 2298.]