OTTAWA (Reuters) - The Supreme Court of Canada agreed on Thursday to take another look at a decision it made in 1993 upholding a ban on assisted suicide, setting up a new battle over the right to die.

Gloria Taylor gives a thumbs up during a news conference in Vancouver, British Columbia June 18, 2012. Taylor , who suffers from Lou Gehrig's disease, won the right to die when the British Columbia Supreme Court ruled to suspend the law banning physician-assisted suicide last week. REUTERS/Andy Clark

The case involves Gloria Taylor, an Amyotrophic Lateral Sclerosis (ALS) patient and activist, who joined the right to die lawsuit in 2011. Taylor died of her illness, informally called Lou Gehrig’s disease, in 2012.

The family of a second woman, Kay Carter, who traveled to Switzerland to end her life, were also plaintiffs. Assisted suicide is legal in Switzerland, along with a handful of other European jurisdictions and a few U.S. states.

“This is a big one dealing with something we will all one day face - how, when and under what circumstances we head for the exit sign,” said constitutional lawyer Eugene Meehan, who has argued numerous cases before the court.

Canada’s Supreme Court last considered assisted suicide two decades ago with the case of Sue Rodriguez, who also suffered from ALS.

The court ruled nobody could legally assist in another’s death, regardless of terminal illness, pain, prolonged suffering or an expressed wish to die.

A lower court in the western province of British Columbia has since struck down Canada’s ban on assisted suicide. But the B.C. Court of Appeals reversed the decision last year and made it clear that any reversal of the ban would have to be done by the Supreme Court.

The Supreme Court majority was a narrow 5-4 in the 1993 Rodriguez decision that it was constitutional to prohibit doctor-assisted suicide. Meehan noted that the sole judge left on the court from that time is Beverley McLachlin, now chief justice, and she was in the dissent.

Since 1993 pressure for assisted suicide has persisted. Last year the Quebec government introduced a bill to legalize it, arguing this was a matter of health care under provincial jurisdiction, not a criminal matter in the federal bailiwick.

Opposing it are religious groups as well as organizations representing people with disabilities, which argue that making it easier to end people’s lives is a slippery slope that makes them feel vulnerable.

In her 1993 dissenting opinion in Rodriguez, McLachlin admitted to some evidence in other countries “that legal codes which permit assisted suicide may be linked to cases of involuntary deaths of the aging and disabled.”

However, she wrote that such unwanted actions should be caught by Canada’s Criminal Code, which could be strengthened if necessary by requiring a judge’s order to allow doctor-assisted suicide.

One principle guiding courts generally is that of “stare decisis,” meaning that precedents should stand. However, the rule is not cast in stone, and Meehan said the Supreme Court of Canada has tended to be willing to revisit specific areas after about a decade.

The name of the current case is Lee Carter et al. v. Attorney General of Canada et al. (35591)