The cases of Kathleen (Kay) Carter and Gloria Taylor are at the heart of the constitutional debate in Canada on medically-assisted death on which the Supreme Court ruled on Friday.

The country's highest court unanimously overturned a legal ban on doctor-assisted suicide, ruling that doctors may help in specific situations. It applies only to competent adults with enduring, intolerable suffering who clearly consent to ending their lives.

Carter, who suffered from a degenerative spinal condition, died at an assisted-suicide clinic in Switzerland in 2010, and Taylor, who had Lou Gehrig's disease and wanted help ending her life, died of an infection in 2012.

Before she died, Taylor had joined forces with Carter's family to launch the constitutional challenge to the Criminal Code prohibition on assisted suicide.

The ruling comes 22 years after the court rejected the claim of Sue Rodriguez, who was dying of amyotrophic lateral sclerosis (ALS). The 5-4 ruling in 1993 concluded the state’s purpose in banning assisted suicide was legitimate in order to protect the sanctity of life.

The decision to hear arguments again on assisted suicide comes in light of two rulings: a June 2014 Quebec ruling in which the province adopted its own law allowing it and more significantly, a 2013 B.C. Appeals Court Ruling that upheld Section 241(b) of the Criminal Code prohibiting aiding or abetting a person to commit suicide.

The B.C. ruling, however, stated that 241(b) violates sections 7 and 15 of the charter. As a result, the B.C. Civil Liberties Association appealed the B.C Supreme Court’s decision.

That appeal teed up the fight over sections 7 and 15 of the Charter. The first guarantees the right to life, liberty and security of a person, and the second ensures equal treatment before the law for all — which right-to-die advocates have argued is violated when people who are physical disabled are not able to take their own lives, as able-bodied individuals are.

However, opponents say those sections of the charter are violated if vulnerable people, the very old or infirm people with severe disabilities, for example, are pressured into having doctors help them die.

Recent opinion polls suggest there is broad public support for the legalization of assisted suicide.

The Supreme Court court has given federal and provincial governments 12 months to craft legislation to respond to the ruling, but the ban on doctor-assisted suicide stands until then. If the government doesn't write a new law, the current one will be struck down.

We take a look at where legislation stands today, in Canada and abroad.

Canada

Kay Carter travelled to Switzerland in 2010 with members of her family to end her life with the help of the assisted-suicide organization Dignitas. ( Canadian Press) Criminal Code Section 241 (b) — and carries a maximum sentence of 14 years in prison. Helping a person commit suicide is a crime in Canada — spelled out inand carries a maximum sentence of 14 years in prison.

The first doctor to be sentenced under the law was Maurice​ Généreux, who got a jail term of two years less a day and three years' probation in 1998 for prescribing sleeping pills to two men with AIDS who were depressed but not terminally ill. One of the men survived and later launched a civil suit against Généreux.

The constitutionality of the law has been challenged before, by Sue Rodriguez, who suffered from Lou Gehrig's disease​ and took her fight to the Supreme Court of Canada and lost in 1993. She died with the help of a doctor less than half a year after the court ruling.

number of Canadians have been prosecuted for helping ill patients or loved ones die. Marielle Houlle, for example, was sentenced to three years probation by a Quebec court in 2004 for helping her 36-year-old son, who suffered from multiple sclerosis, end his life. have been prosecuted for helping ill patients or loved ones die. Marielle Houlle, for example, was sentenced to three years probation by a Quebec court in 2004 for helping her 36-year-old son, who suffered from multiple sclerosis, end his life. Lee Carter accompanied her 89-year-old mother to a dying with dignity clinic in Switzerland in 2010 and is a plaintiff in the Supreme Court case. (Darryl Dyck/Canadian Press)

In 2007, B.C. Dr. Ramesh Kumar Sharm was given a conditional sentence of two years less a day and had his physician's licence revoked after prescribing a lethal dose of drugs for a 93-year-old patient.

Canada does allow doctors to induce a coma and turn off life-sustaining equipment for suffering patients near death, a practice known as palliative sedation that right-to-die advocates argue is ethically, morally and legally no different than assisted suicide or euthanasia.

Quebec

In June 2014, Quebec broke new ground when it passed the Act Respecting End-of-Life Care, bypassing the Criminal Code by incorporating medically assisted death into provincial health care legislation. The new law is expected to come into force by the end of 2015 and allows people with a terminal illness that is causing unbearable suffering to ask a physician to administer a lethal dose of medication.

"Quebec was a groundbreaker in terms of saying, 'We're not talking about assisted suicide or homicide… but we're talking about end of life: this is a natural extension of palliative care, so it needs to come under provincial legislation,' " said Wanda Morris, CEO of the advocacy group Dying With Dignity Canada.

Under Quebec's legislation, a patient must request medical aid in dying, and the physician who is providing the aid must confer with a second physician and other members of the patient's medical team and must verify that the patient has made the request freely and in an informed way. The physician must administer the aid themselves — in a medical facility or the patient's home — and take care of the patient until death.

United States

Assisted-suicide laws in the U.S. allow the practice only for those who are critically ill and have six months or less to live, and the rules require the patient to administer the medication themselves.

Vermont: The latest state to legalize assisted suicide. Under regulations passed in May 2013, a patient must verbally request to die at least 15 days in advance and again — verbally and in writing — 48 hours prior to taking lethal drugs. Two physicians determine whether the patient qualifies, which means they must have an "incurable and irreversible disease" and no more than six months to live.

Oregon: The first state to pass a law allowing physician-assisted suicide. Enacted in 1997, the law was challenged in subsequent years but was upheld by the U.S. Supreme Court in January 2006. To date, about 750 people have died from lethal doses of medications prescribed under the act, according to data compiled by state health authorities.

The law stipulates that the patient must have been declared terminally ill by two physicians and must have requested lethal drugs three times, including in writing.

Washington: The Death With Dignity Act went into effect in March 2009 and has similar stipulations to assisted-suicide legislation in other states.

Vermont Gov. Peter Shumlin signed the state's assisted-suicide legislation into law in May 2013, making it the third state to have such a law on the books. (Jim Cole/Associated Press)

Montana: The state does not have a law legalizing assisted suicide, but in December 2009, the Montana Supreme Court ruled that a physician who helps a mentally competent, terminally ill patient end their life should not be held criminally liable if the patient has given consent.

New Mexico: An Albuquerque judge ruled in January that it is a constitutional right for a mentally competent, terminally ill patient to seek aid in dying. The challenge to the state's prohibition on assisted suicide was brought forward by two doctors who wanted to help a 49-year-old patient suffering from terminal cancer end her life. The state attorney general has appealed.

Europe

European laws on medically assisted death are broader than those in the U.S., with most allowing physicians to prescribe and administer lethal drugs and not setting conditions tied to life expectancy.

"The eligibility is not restricted to terminal illness. It includes a medical condition but also unbearable suffering," Morris said.

The Netherlands: Legislation legalizing assisted suicide and euthanasia was introduced in 2002, but the country's courts have permitted these actions since 1984.

Dutch doctors must follow a narrow set of guidelines when helping patients end their life: The patient, who must be suffering unbearably and have no hope of improvement, must ask to die. The patient must clearly understand the condition and prognosis and a second doctor must agree with the decision to help the patient die.

The government of Belgian Prime Minister Elio Di Rupo lifted the age limit on assisted suicide, allowing it even for those younger than 18 as long as they are terminally ill and have the consent of their parents and doctors. (Yves Logghe/Associated Press)

The law allows for assisted suicide in cases of dementia but only if a prior directive from the patient exists. Children of 16 and 17 don't need parental consent to undertake assisted suicide but must involve parents in their decision.

Belgium: It legalized euthanasia and physician-assisted suicide in 2002 and, in February 2014, removed the age limit of 18, allowing assisted suicide for children as long as they are terminally ill, suffering unbearably and conscious of their decision, and have the consent of their parents and doctors.

Under the Belgian law, the patient must ask to die and two doctors must sign off on the request, as well as a psychologist if the patient's competency is in doubt. The doctor and patient negotiate whether death is to be by lethal injection or prescribed overdose.

Switzerland: Assisted suicide has been allowed since 1942, but euthanasia is forbidden, with patients having to administer the lethal medication themselves. Unlike other countries, Switzerland does not specify any criteria for who can assist with a suicide — as long as they are not motivated by immoral or financial reasons — and how ill the patient must be.

Right-to-die organizations such as Dignitas help carry out assisted suicides, providing counselling and lethal drugs. Death by injection is banned.

Switzerland also allows non-citizens to seek assisted suicide in the country, and several Canadians have done so over the years, including one of the plaintiffs in Friday's Supreme Court case.

Luxembourg: This country of about 600,000 people passed a law legalizing euthanasia and assisted suicide in 2009 with conditions similar to those in the Netherlands.

Other cases of note

Britain: Assisted suicide carries a maximum prison sentence of 14 years, but in 2010 the director of public prosecutions published an assisted suicide policy that allows prosecutors to examine each case on its merits and decide whether there is a public interest in prosecuting. Euthanasia can be prosecuted as manslaughter or murder, with a maximum sentence of life in prison.

Colombia: The predominantly Catholic country doesn't have a law explicitly condoning assisted suicide, but its Constitutional Court ruled in 2010 that a doctor who helps someone die cannot be prosecuted for euthanasia, which is a crime under Colombian law, as long as the patient had a terminal illness and gave their consent.