RUTHFULLY YOURS

True, the Germans built Auschwitz and other death camps on Polish soil. But the Germans could not have murdered the Polish Jews, and millions of other Europeans imported to death camps in Poland, without the active assistance of many Poles in identifying and rounding up victims. This complicity was incited by generations of anti-Semitic church sermons. Poles also murdered Jews during and after the German occupation—including in the Jedwabne pogrom in July 1941 and in Kielce in July 1946.

On the positive side, there were Polish Catholics, including priests and nuns, who risked their lives protecting Jews. There were many other righteous Polish individuals as well. Jan Karski risked his life by dressing as a death-camp guard so he could document the horrors, and the Ulma family was murdered for harboring Jews.

Poland’s role in the Holocaust is a mixed picture of complicity, heroism, complacency and willful blindness. It is up to historians to sort out the specifics and moralists to apportion blame. But it is not the role of law to stifle debate and to threaten those who question the current self-serving Polish government narrative.

Nor does history need laws to confirm that the Holocaust occurred. Yet several European governments have made Holocaust denial a crime. Denying the Armenian genocide is a crime in France; acknowledging it is a crime in Turkey. Israel’s Knesset is responding the Polish effort by weighing its own legislation that would make it a crime to deny or minimize the role of collaborators in the Holocaust. Both the proposed Polish and Israeli laws would have extraterritorial reach, so virtually any discussion or debate about this issue would risk prosecution and imprisonment in one of those countries. Such is the consequence of governmental efforts—no matter how well-intentioned—to criminalize debates about history.

It is understandable why people who believe there is only one side to a debate would seek to censor what they regard as malicious lies about deeply emotional issues such as the Holocaust and the Armenian genocide. It is also understandable that some American students and faculty, particularly on the hard left, seek to stifle “hate speech,” “micro-aggressions” and comments or ideas that make them feel “unsafe.”

But censorship comes around like a boomerang. To some Palestinians on campuses, Zionist speech creates an unsafe space, while to some Jewish students, anti-Israel speech offends and frightens. To some women, antiabortion advocacy is demeaning, while to some Christians, pro-abortion advocacy is offensive. It is not the role of governments or universities to take sides in these conflicts. It is very much their role to encourage civil discourse on these and other controversial issues that divide people emotionally and intellectually. It is also the role of these institutions to promote tolerance of conflicting views and to tell citizens and students that, in a democracy, there are no safe spaces from ideas.

So let the competing narratives regarding the role of Poland, the Polish Catholic Church and individual Poles continue to be debated without the heavy hand of governmental censorship and criminal punishment. Trust the open marketplace of ideas, rather than the self-serving biases of bureaucrats, to arrive at the complex truth about this terrible period in Polish and Jewish history.

Mr. Dershowitz is a professor emeritus at Harvard Law School and author of “Trumped Up! How Criminalizing Politics Is Dangerous to Democracy” (CreateSpace, 2017).