While 33-year-old Nancy Cruzan lies comatose in a Missouri hospital, as she has for the past eight years, the legal battle in her name goes on.

Undeterred by a U.S. Supreme Court ruling against them last June, Lester and Joyce Cruzan have gone back to court in yet another effort to force doctors to disconnect the artificial feeding tube that keeps their irreversibly brain-damaged daughter alive. Their latest petition for a rehearing in the case cites "newly discovered evidence" that Nancy Cruzan would have preferred death to her current helpless condition.

This time, the Cruzans appear to have a better chance of winning. For one thing, the state of Missouri, which in the original case fought the Cruzans all the way to the Supreme Court, will not do so again. Missouri Atty. Gen. William L. Webster last month filed a motion asking the judge to dismiss the state from the case.

Officially, the reason Webster cited in withdrawing from the case is that with the Supreme Court's June 25 decision, "we see no reason for the state's involvement in a new probate proceeding." Unofficially, others involved in the case note that public opinion has sided heavily with the Cruzans and that Webster is said to be planning to run for governor in 1992.

"The public sentiment has shifted in the state of Missouri," said Ronald E. Cranford, a neurologist who has advised the Cruzan family. "It's not politically advantageous to be against the Cruzan family anymore."

"There's no political mileage in it," said George Annas, professor of health law and director of the law, medicine and ethics program at Boston University. "It's hard to find anyone who thinks that Nancy Cruzan should not be disconnected from the feeding tube."

Nancy Cruzan has been kept alive by artificial feeding through a tube since she was brain-damaged in a car accident in 1983. Medical experts agree that she is in a "persistent vegetative state," with no chance of regaining consciousness. She can breathe on her own and retains motor reflexes, but she lacks all cognitive function and sensation -- thinking and feeling, doctors say.

Her parents first asked to have the feeding tube withdrawn in 1987, but the hospital refused to do so without court backing. The Cruzans went to court. Jasper County Circuit Court Judge Charles E. Teel's ruling in their favor was overturned on appeal, 4 to 3, by the state Supreme Court. Last June, in its first "right to die" decision, the U.S. Supreme Court upheld the Missouri ruling in a 5-to-4 decision. The high court said it was constitutional for Missouri to require "clear and convincing" evidence of a patient's wish before allowing withdrawal of life-sustaining treatment, including artificial nutrition and hydration.

Nancy Cruzan left no living will. Her parents argued that being kept alive indefinitely by artificial means without hope of recovery gave her no dignity or quality of life and that she would have preferred to die. They cited unwritten comments she had made to substantiate that belief.

In their latest petition, the Cruzans cite new evidence, including "three witnesses" who have "come forward who had specific discussions with Nancy regarding her wishes about life-sustaining medical treatment." When their testimony is added to statements already presented at the first trial in 1988, the Cruzans said, "the evidence is absolutely compelling" and "more than meets" the state's "clear and convincing" standard upheld by the Supreme Court.

Judge Teel has scheduled a hearing Nov. 1 on the Cruzans' petition and the state's motion to withdraw from the case. Lawyers in the case expressed hope that it could be settled by the end of the year.

With the state no longer involved, a ruling by Teel in favor of the Cruzans this time might end the case -- and Nancy Cruzan's life.

"If the state withdrew, then this time there wouldn't be anybody to object," said John H. Pickering, a lawyer who chairs the American Bar Association's Commission on Legal Problems of the Elderly and represented the American Academy of Neurology in the Cruzan case.

Even the court-appointed guardian for Nancy Cruzan, Missouri attorney Thad C. McCanse, has publicly said he has no disagreement with the Cruzans' request to withhold artificial feeding from their daughter.

Although the Supreme Court's Cruzan decision applies only to the state of Missouri, it carries symbolic importance throughout the country, Annas said.

Physicians who are already nervous about the risk of malpractice lawsuits, he said, are even more likely to refuse to withhold extraordinary life-continuing care from irreversibly comatose patients unless they have a living will or signed power of attorney form.

"It's becoming very hard to terminate treatment on anyone in this country," Annas said. "The Cruzan decision is having that horrible effect -- of physicians starting to practice law, basically."

Meanwhile, the subject of all this litigation, Nancy Beth Cruzan, lies unconscious in the Missouri Rehabilitation Center, a state facility in Mount Vernon. She is cared for at public expense, at an estimated cost of $130,000 a year. Cruzan is one of five patients at the Missouri facility -- and one of an estimated 10,000 nationwide -- who exist in a kind of coma that medicine refers to as a persistent vegetative state.

Cruzan's brain injuries resulted from an automobile accident in 1983. She was thrown about 35 feet from the car and landed in such a way that her airway was blocked, cutting off the vital supply of oxygen to her brain. The lack of oxygen destroyed most of her brain but left intact the brain stem at the top of the spinal cord, which controls reflexes and involuntary functions such as breathing, heartbeat and circulation. She can breathe on her own but cannot swallow. She feels no pain. Her only movements are from physical reflexes.

"Nancy is very representative of persistent vegetative-state patients," said Cranford, the neurologist from Minneapolis who is a consultant to the Cruzan family and who has examined Nancy Cruzan. "They can breathe on their own, their heartbeat and respiration are okay. But those things that make us uniquely human are gone. Even with good nursing care, which she has gotten, Nancy is gone as Nancy."

The only outward indications of her disability, he said, are the bloating of her face and the tightening of her joints -- known as contractures -- from lack of movement over the years. "She looks normal except for her bloated face," Cranford said. "She's just there, like all persistent vegetative-state patients. But in fact they're not really there at all. It's kind of a cruel hoax that nature and medical technology have played on us."

An artificial feeding tube leads through the abdominal wall into her stomach, and several times a day Cruzan receives fluids and liquid nutrients from a plastic bag.

"That's her medical care," Cranford said.

"Her eyes are open much of the time," he said. "She appears normally awake, yet she is just as unconscious as someone in a coma or someone who's brain dead or dead dead.

"That's the hard thing on the family. She looks alive and can live for years. It's very hard for everybody to fully appreciate that she's totally unconscious and yet may survive for years if given food and water."