Florida's highest court ruled unanimously Thursday that Gov. Jeb Bush (R) violated a "cornerstone of American democracy" when he overrode a court decision and ordered doctors to resume tube-feeding a severely brain-damaged woman.

Chief Justice Barbara J. Pariente of the Florida Supreme Court called Bush's actions in the case of Terri Schiavo "an encroachment on the judicial branch" that undercut the constitutionally protected separation of powers among the executive, legislative and judicial branches.

The decision does not mean that Schiavo, who has been in a vegetative state since going into cardiac arrest 14 years ago, will be immediately removed from life-support systems, lawyers involved in the case said. But the emphatically worded opinion leaves a dwindling field of options for Bush, who has sided with Schiavo's parents in a bruising legal battle to stop her husband from having her disconnected from the feeding tubes that are keeping her alive.

Bush spokeswoman Jill Bratina said the governor's legal team is reviewing options, including an appeal of the Florida Supreme Court decision and a possible appeal to the U.S. Supreme Court. The governor remains concerned, Bratina said, that Schiavo and her parents may have been denied due process.

"From a moral standpoint, that to him is very troubling," Bratina said. "Someone who is on death row for murder is given due process."

Attorneys for Schiavo's husband, Michael Schiavo, accused Bush of needlessly prolonging a legal case that has been rejected by multiple Florida circuit and appeals courts.

"Given the track record of the governor, we would be naive in saying that this would be over quickly," said Randall Marshall, legal director of the Florida chapter of the American Civil Liberties Union, which represents Michael Schiavo. "It certainly seems to be a political decision that there's mileage to be gained by injecting the state into private decisions."

Schiavo's saga has become a touchstone in the heated national debate over right-to-die cases. She left no written instructions, but her husband has said that she would not have wanted to live in a vegetative state.

Her parents, Robert and Mary Schindler, have argued that videotapes of her appearing to smile and fluttering her eyelids are proof that she has cognitive abilities. But courts have rejected their suggestions that experimental therapies could revive her.

Doctors removed Schiavo's feeding tubes in October after Michael Schiavo won a state court case. The Schindlers mounted a media campaign to save their daughter's life, and groups from across the country inundated Bush's office with e-mails, letters and phone calls urging him to intervene. At his urging, the Florida legislature quickly passed "Terri's Law," which gave the governor the right to order feeding resumed. He issued an executive order six days after Schiavo's feeding was stopped, and she has been on life-support systems since.

The law and Bush's order, which were condemned by many bioethicists, were overturned Thursday by a seven-member Supreme Court that includes three Bush-appointed justices. The others -- including the opinion's author, Pariente -- were appointed by his Democratic predecessor, Lawton Chiles.

Pariente wrote that allowing Bush's executive order to stand would mean that "no court judgment could ever be considered truly final and no constitutional right truly secure."

"Vested rights could be stripped away based on popular clamor," the opinion said. "The essential core of what the Founding Fathers sought to change from their experience with English rule would be lost."

"Our hearts" comprehend the pain of Schiavo's family, Pariente wrote. "But our hearts are not the law."

Special correspondent Catharine Skipp contributed to this report.

Terri Schiavo, who is the subject of the case, has been in a vegetative state for 14 years.