Raphael Lemkin was a dogged campaigner with a burning faith in the power of language and the law. He changed the world with a word and yet remains virtually unknown.

Born in 1900 in Belarus, he studied linguistics, philosophy and law. He became obsessed with a crime that, at that point, had no name: the mass murder of groups, simply because of their identity. He was aware of the Turkish massacre of Armenians and of the Assyrians murdered in Iraq -- unpunished crimes that would allow Hitler to believe his final solution could be achieved without international intervention. Lemkin identified the stages that led to mass murder: the demonisation of a group, the destruction of its culture, restriction of its freedoms and rights, the small rehearsals of extermination.

In 1933 Lemkin, then working as public prosecutor in Poland, presented a paper to the League of Nations legal committee in Madrid that described what he then referred to as "the Crime of Barbarity" and its prevention. His statement lost him his job, but he continued to pursue the idea that the rule of law could save us from even the gravest crime.

When the Nazis invaded Poland, Lemkin -- a Jew -- was wounded defending Warsaw. He fled, first to Sweden and then the US. Most of his family were murdered in the Holocaust. He'd been unable to prevent what he had guessed was coming and spent the rest of his life battling what he came to call genocide. He named and defined humanity's ultimate crime and was the prime mover behind the 1948 UN Convention on the Prevention and Punishment of the Crime of Genocide. He worked himself to death to establish a legal framework that defends us all. That politicians have consistently failed to use the tools he gave them is their shame and not his. He was a remarkable man.