I write at a historical yet painful moment of remembrance and reminder: the 70th anniversary of the Shoah of Hungarian Jewry, when some 600,000 Jews, three-quarters of that country’s Jewish population, perished in 1944. It has also been 70 years since the rescue of the remnant of Hungarian Jews by Raoul Wallenberg, the disappeared hero of the Holocaust, who demonstrated that one person can confront evil, can resist, can prevail, and thereby transform history.I write also having participated in the March of the Living in Budapest this past Sunday, and then on Monday in Auschwitz. In Budapest, I joined tens of thousands of Hungarian Jews and their supporters in reenacting the death march from the Danube River to the eastern railway station. In a period of 10 weeks, 430,000 Hungarian Jews were herded onto cattle cars at that station and deported to Auschwitz.Those 10 weeks represent the fastest and most brutally efficient extermination of the Shoah.Adolf Eichmann, the Nazi desk murderer, arrived in Budapest in March 1944 to organize and supervise the mass deportation. To Eichmann, Raoul Wallenberg was the judenhund, “that Jewish dog Wallenberg.”For the remnant of Hungarian Jews that Wallenberg saved – many of whom I have come to know over the years – he was a guardian angel. As for Wallenberg, as he put it, “For me there was no other choice.”In Auschwitz, I visited the death camp together with Cecilia Ahlberg, Wallenberg’s great-niece, who was there for the first time.The exhibit in the first barracks we visited, building number 4, bore witness to horrors too terrible to be believed, but not too terrible to have happened. It described how, from 1942 to 1945, 1.3 million people were murdered at Auschwitz, of whom 1.1 million were Jews, recalling Elie Wiesel’s dictum: “The Holocaust was a war against the Jews in which not all victims were Jews, but all Jews were victims.”Inscribed on the wall were the incendiary words of the Nazi Otto Frank (not to be confused with Anne Frank’s father), screaming out at us: “Jews are a race that must be totally exterminated.”Indeed, by 1944, the cattle trains from Budapest went directly to the crematoria.In an adjacent barracks, the Yad Vashem exhibit contained film excerpts from the incendiary and annihilationist rhetoric of Nazi leaders.From Hitler writing in Mein Kampf in 1924, to Goebbels and others in the 1930s, one witnessed the dehumanization and demonization of the Jew – referred to as the “devil” and “embodiment of evil in the world” – as prologue to and justification for the Holocaust.As the Supreme Court of Canada has put it, “the Holocaust did not begin in the gas chambers, it began with words.”The Yad Vashem exhibit contained poignant drawings by children in all their innocence, and unaware of the horrific fate that was to befall them, a reminder that 1.5 million Jewish children perished in the Holocaust.Following the visit to the barracks, I was invited together with Ahlberg to lead the march from Auschwitz to Birkenau, along with judges of the Israeli Supreme Court, including its President Asher D. Grunis. As fate would have it, I first met Justice Grunis when he arrived as a graduate student in 1972 at Osgoode Hall law school in Toronto where I was a professor at the time. We were joined in the front line by former Israeli Chief Rabbi Yisrael Lau, himself a Holocaust survivor, who has addressed every March of the Living since its inception in 1988, and whose stories and teachings during this march – and his powerful address at the closing ceremony, when he spoke directly to survivors – were unforgettable.Indeed, the march from Auschwitz to Birkenau, during which I marched carrying a Torah scroll, and the closing ceremony at Birkenau, was one of the most memorable and inspiring moments I have ever experienced, the emotional riposte to the overwhelming pain of the visit to the Auschwitz barracks hours before.While this was not my first visit to Auschwitz and Birkenau, the cataclysm of emotions on this occasion, from the heartbreaking visit to the barracks to the inspirational march in the company of survivors, students, rabbis, and judges of Israel’s Supreme Court, was particularly stirring.At the closing ceremony, I was invited to light one of the six memorial candles together with Ahlberg, who then spoke softly and powerfully about her first visit to Auschwitz, and the meaning of the heroism of her great-uncle Raoul Wallenberg, who showed how one person with the compassion to care and the courage to act could transform history. I spoke after her, and, moved by her words and overtaken by emotion, I said: “What makes the Shoah – and the Rwandan genocide, the 20th anniversary of which we are also now commemorating – so unspeakable is not only the horror of it, but the fact that it was preventable.Nobody can say the world did not know. The mass deportation and death of Hungarian Jews took place in 1944, at the war’s end. The bystander world community knew, but did not act.Raoul Wallenberg did.”I thought to myself – though time did not permit saying so out loud – that the Holocaust of Hungarian Jews had actually begun in the 1930s, when Hungary enacted Nuremberg race laws in 1938, when Jews were already suffering discrimination, exclusion and dispossession, and when 20,000 Hungarian Jews were already deported and murdered in 1941.The March of the Living concluded – as it had the day before in Budapest – with El Malei Rachamim, the funeral prayer powerfully sung by a father and son duo, the father a cantor in Australia, the son a cantor in Tel Aviv.Five Holocaust survivors, all Canadian, then said kaddish before a powerful, uplifting singing of “Hatikva.” I felt again that my heart would break, but this time with joy. On my left was Supreme Court Justice Daphne Barak- Erez; on my right, a disabled survivor who struggled to his feet as he sang with tears streaming down his face.When we concluded the heroic, inspiring refrain, we burst into exclamations of “Am Yisrael Chai.”Irwin Cotler is a member of the Canadian Parliament, former minister of justice and attorney-general of Canada, and professor of law (emeritus) at McGill University in Montreal.