Final answer:
Voluntary passive euthanasia is legal in the United States, involving terminally ill patients consenting through advanced directives to forgo life-extending treatments. Nonvoluntary passive euthanasia does not involve the patient's consent and is more complex legally and ethically.
Step-by-step explanation:
Passive euthanasia, a practice where life-sustaining treatment is withheld, can be divided into two types: voluntary passive euthanasia and nonvoluntary passive euthanasia. Voluntary passive euthanasia is legal in the United States and typically involves the decision to not pursue life-saving measures based on a patient's consent, often expressed through an advanced directive like a DNR (Do Not Resuscitate) order. Nonvoluntary passive euthanasia, on the other hand, occurs in the absence of the patient's consent when they are incapable of making such decisions, and is a more ethically and legally complex issue.
An example of voluntary passive euthanasia would be a terminally ill patient who, via an advanced directive, has stated their wish to forgo specific life-extending treatments. Contrastingly, nonvoluntary passive euthanasia might involve a patient in a persistent vegetative state without an advanced directive, requiring a surrogate decision-maker to guide end-of-life care choices.