Opposing such a right, religious conservatives warn that government is entering dangerous and unholy territory when it allows doctors and patients to determine when life should end, and there is a very short distance between choosing to die voluntarily and choosing to die under pressure from family and medical bills.
The right to die, at least the right to a do-not-resuscitate order, is fairly well established, and hard to attack in court. But a rising storm is brewing, pitting those patients who do not want to be kept alive by extraordinary measures and those medical professionals or institutions who say they will not perform procedures that outrage the conscience.
People with opposing views are already battling in the lower courts, but any final resolution would have to be hammered out on the anvil of the U.S. Supreme Court, which has shown increasing sympathy for the right to die but has never ruled on the right of conscience.
The right to die and the right to refuse also are issues in healthcare reform legislation, with opponents complaining the bill contains nothing to rein in the do-not-resuscitate procedure or other procedures like abortion.
Shortly before getting out of Dodge in December 2008, the Bush administration issued a tough "conscience protection" rule for the healthcare industry.
The rule gave doctors, hospitals and other hospital workers and volunteers the right to refuse to participate in medical care they find morally objectionable. Though aimed at abortion, the right-to-refuse rule applied to all procedures, even birth control, in vitro fertilization and stem cell research.
Any medical care provider who violated that right-to-refuse could be charged with discrimination and lose federal funds. The Obama administration took steps to reverse the rule almost as soon as it took office but anti-abortion groups managed to stall the effort.
The issue became more complicated in November, when the U.S. Conference of Catholic Bishops approved a revised directive saying in part Catholic health facilities have "an obligation to provide patients with food and water, including medically assisted nutrition and hydration for those who cannot take food orally."
The directive affects 600 Catholic hospitals in the United States, which admit 6 million patients annually, and thousands of nursing homes and related facilities.
"This obligation extends to patients in chronic and presumably irreversible conditions," such as a persistent vegetative state, who might live for many years if given such care, the directive said, Kaiser Health News reported last month.
A patient's advance treatment instructions or the designated proxy's decisions in end-of-life situations must be honored in most states, or else the patient must be transferred to a facility that will honor those wishes, KHN said. On the other hand, it is against the law in every state to use a feeding tube or other extraordinary end-of-life measures against the expressed wishes of the patient, the report said.
The bishops' directive said a feeding tube was not required if it would not prolong life, would be "excessively burdensome for the patient" or would "cause significant physical discomfort."
Hospitals and nursing homes do not have to comply with requests that are "contrary to Catholic moral teaching," in line with a longstanding policy that, as in the case of the revised directive, applies to non-Catholic patients as well, KHN said.
If a patient or family did not want a feeding tube "and the reason they don't want it is they basically want to die, then the Catholic institution would explain to them they can't cooperate with that and they would have to go to another institution," KHN quoted the Rev. Thomas G. Weinandy as saying. Weinandy is the executive director for doctrine at the bishops' conference, who helped draft the policy.
KHN said no other large healthcare systems in the United States have nutrition and hydration policies like those outlined in the bishops' directive.
Catholic officials and outside experts say the directive may apply to a wider range of patients, those having "chronic and presumably irreversible conditions," including those with massive strokes, advanced Alzheimer's disease, traumatic brain injury and Lou Gehrig's Disease, KHN reported.
KHN said the revised directive arises from statements made in 2004 by Pope John Paul II in 2004 during the legal battle surrounding Terri Schiavo, and from clarifying statements by Vatican officials in 2007.
The fierce battle in the Schiavo case is an example of the depth of feeling people have on the issue.
Schiavo collapsed at her St. Petersburg, Fla., home in 1990 with cardiac and respiratory arrest. Deprived of oxygen, her brain suffered irreparable damage and she was institutionalized for 15 years. Her husband, who after a number of years had started a new relationship, insisted Schiavo did not want to be kept alive by a feeding tube; her Catholic parents and brother insisted just as strongly that she had awareness and might recover.
Eventually, after President George W. Bush, state officials and Congress, among others, joined in support of her parents -- one middle-aged woman protester outside Schiavo's nursing home tried to march by security with a cup of water -- the U.S. Supreme Court rejected review of the case and the state courts sided with her husband in 2005. She was disconnected from her feeding tube and died a couple of weeks later.
An autopsy found her brain irreparably damaged throughout, and only half of its original size.
But the hurt inflicted in the Schiavo case lingers.
When Robert Schindler Sr., Schiavo's father, died last August of heart failure, right-to-life organizations from around the United States sent their condolences, the St. Petersburg Times reported.
"After Terri's death, my father was never the same," her brother Bobby Schindler said though a spokesman. "I am heartbroken over the loss of my father, and yet I know at this moment he is rejoicing with my sister."
Recent Supreme Court decisions show some support for the right to die, such as refusing to intervene in the Schiavo case. The justices also refused to intervene several times in the cases against Dr. Jack Kervorkian, Michigan's "Dr. Death" who served eight years in prison for assisted suicide.
In 2006 the justices decided 6-3 that the U.S. attorney general could not prosecute doctors assisting in suicides under the Oregon Death With Dignity Act (Washington state has a similar law).
The Montana Supreme Court got into the dispute with a 5-2 decision last December. The Montana ruling did not address the constitutional issues surrounding doctor-assisted suicide, but said a physician was not liable under state law or "public policy" for giving a terminal patient a drug that the patient himself could use to end his own life.
State Justice Jim Rice, in dissent, said the ruling "ignores expressed (legislative) intent, parses statutes, and churns reasons to avoid the clear policy of the state and reach an untenable conclusion. ... In my view, the court's conclusion is without support, without clear reason and without moral force."
In an opinion concurring with the majority, state Justice John Warner explained why he thought the court ruled the way it did.
"The state has failed to explain what interest the government has in forcing a competent, incurably ill person who is going through prolonged suffering and slow, excruciating physical deterioration to hang on to the last possible moment," he wrote. "Moreover, the state has not come close to showing that it has any interest, much less a 'compelling' one, in usurping a competent, incurably ill individual's autonomous decision to obtain a licensed physician's assistance in dying so that she might die with the same human dignity with which she was born."