In the Quinlan case, the court allowed a competent patient to terminate the use of life-sustaining medical machines to prolong life. Since New Jersey's decision, all fifty states have enacted similar statutes which contain living will provisions. However, although the United States Supreme Court upheld the Quinlan decision in re Cruzan , it changed the parameters of passive euthanasia . With the Cruzan decision, the Supreme Court held that passive euthanasia was legal but only for competent adults or those who are incompetent but have previously procured a living will. However, if the patient is without a living will and incompetent, it becomes the burden of the family to prove that there is clear and convincing evidence to the affect that the patient does not want to continue living in a vegetative state. As to active euthanasia, there has been no Supreme Court ruling determining whether the right to die, as understood in passive euthanasia cases, can be bound over to active euthanasia. The decision is thus left to the individual states. Currently, thirty-one states have criminalized explicitly the act of assisted suicide . Physician-assisted suicide is generally recognized as illegal under the parameters of homicide, however it is very difficult to meet all of the elements of the crime and conviction subsequently becomes nearly impossible. The fact that the U.S. Supreme Court has not reviewed a physician-assisted suicide case, which would create precedent, constitutes a dilemma for the state courts in that there is no uniform test or ruling by which to decide. Most states have developed their own laws to, more often than not, make doctor-assisted suicide illegal. However, when a case comes to trial it is usually dismissed either by the judge in a pretrial motion or by the jury. For example, in at least three of the assisted suicides which Dr. Kevorkian was involved in, all criminal charges were dismissed.