Throughout history, people have called for medical practitioners to assist in the deaths of patients suffering from intractable pain as a result of advanced dis- ease. But while many doctors themselves have advocated such assistance, including those of ancient Greece, Western medical practice has generally cleaved to the view of Hippocrates, who argued firmly against phy- sicians' "giving a deadly drug to any patient."

Not that the Hippocratic view has reigned unchallenged. Today i...