“We are in the presence of a crime without a name,” said British Prime Minister Winston Churchill in 1941, in a radio broadcast in which he described the barbarity of the German occupation of the Soviet Union.

Only a few years later, thanks to the determined and tireless efforts of the Polish Jewish lawyer Raphael Lemkin, this type of atrocity the destruction of entire human groups would have a name and be declared a crime under international law in a treaty that is binding on all states that ratify it: the Convention on the Prevention and Punishment of the Crime of Genocide. While it was too late to save the Jews of Europe, there was a lesson to be learned from the widespread passivity in the face of the Nazi mass killings. As Raphael Lemkin wrote in the postwar years, “by declaring genocide a crime under international law and by making it a problem of international concern, the right of intervention on behalf of minorities slated for destruction has been established.”

December 9 marked the 64th anniversary of the UN’s adoption of the Genocide Convention, which has come to embody a milestone in the history of human rights and the promise of a world free of this odious crime.

We know that this promise, symbolized by the words “Never again,” has not been fulfilled. Still, the Genocide Convention laid vital foundations and has borne significant fruit.

Sixty-four years down the line, mass atrocities cannot be universally ignored. More states have signed the Convention, fewer states believe that sovereignty is a license to kill, many perpetrators have been held accountable for their crimes, and, above all, the international community has shown that it can take collective action to prevent and punish genocide.

Best wishes for a peaceful new year.

Alejandro Baer is the Stephen Feinstein Chair and Director of the Center for Holocaust and Genocide Studies. He joined the University of Minnesota in 2012 and is an Associate Professor of Sociology.