Auschwitz. Treblinka. The Warsaw Ghetto. During World War II, Poland became the epicenter of the Nazis’ crimes—but soon, implying that those crimes were committed by the Polish state will itself be a crime. A controversial new law in Poland makes it illegal to accuse the nation of being complicit with Nazi crimes like the Holocaust. It also outlaws the phrase “Polish death camps.” Both are punishable by prison sentences of up to three years.

The law has provoked an academic and diplomatic firestorm, drawing criticism from historians and rebukes from people like Secretary of State Rex Tillerson, whosaid the law “adversely affects freedom of speech and academic inquiry.” Israel’s memorial to Holocaust victims, Yad Vashem, called the legislation “liable to blur the historical truths regarding the assistance the Germans received from the Polish population during the Holocaust.”

Those historical truths have long been the subject of passionate debate—and are sensitive in Poland, which suffered immense persecution and loss during World War II. Adolf Hitler didn’t just wage war against Poland: He wanted to wipe the country off the map entirely and re-populate it with Germans. Three million Polish Jews were murdered in the Holocaust; another 3 million Polish civilians and military personnel are thought to have perished at the hands of the Nazis. Nearly 18 percent of Poland’s population died during World War II, including 90 percent of Polish Jews, the largest group of Jews murdered in the Holocaust.

Poland’s experience under Nazi occupation was different than that of many of its European neighbors. Occupied Poland’s government did not collaborate with the Nazis—it was replaced by a German administrative government that set about “Germanizing” Poland. This entailed forcing Poles off of their land to make room for Germans, rounding up intellectuals and political elites, prohibiting the Polish language in some areas, and closing or destroying cultural and educational institutions. An estimated 50,000 Polish children werekidnapped by the Nazis, resettled with German elites or killed.

The Nazis saw occupied Poland as the ideal site not only for German resettlement, but also for the extermination of Jews. Hundreds of ghettos and concentration camps were built by the Nazis in occupied Poland, and sixextermination camps, including Sobibor, Auschwitz and Treblinka, were built in occupied Poland between 1941 and 1945.

Though Poland was essentially turned into a police state by the Nazis during the war, the Polish people did fight back. The Polish Resistance became one of the largest underground movements against the Nazis. The Polish government itself never surrendered to the Nazis, notes the United States Holocaust Museum and Memorial; instead, it set up camp in London, where it remained throughout the war.

In addition, many Poles helped their Jewish neighbors. Polish citizens make up thelargest group of Yad Vashem’s Righteous Among Nations, a term used to describe non-Jews who risked death to help Jews during the Holocaust.

However, other Poles murdered Jews. They participated in pogroms in places likeJedwabne, where Polish locals helped the Nazis round up and burn alive hundreds of Jews in 1941. Individual Polestortured or mistreated Jews during the war at death camps and as civilians, and othersdenounced their Jewish neighbors. Pogroms even continued after the war was over, as in Kielce, where 42 Jewish survivors of the war were beaten, shot and stoned by Poles. They were among thousands of Jews who found persecution instead of open arms when they returned home to Poland.

Butaccording to historian Norman Davies, most collaboration between Poles and Nazis was a matter of survival. “In a world where immediate death awaited anyone who contravened Nazi regulations,” he writes, “the Nazis could always exact a measure of cooperation from the terrified populace….Both Poles and Jews were victims to the Terror, and were conditioned by it.”

Debates about Poland’s role in the Holocaust began raging as soon as the war ended. They continue today—in part at the behest of the right-wing, nationalist political party, known as Law and Justice, that has led Poland since 2015. Since Law and Justice’s victory, the Polish government hascourted controversy by cracking down on the media about the language used when discussing the parts of the Holocaust that took place on Polish soil. It has also taken a heavy-handed approach to representations of Polish history, as when itforced a new museum about World War II to merge with one focused on Polish suffering under the Nazis.

The Polish Foreign Ministry has long waged a campaignagainst the term “Polish death camps,” which historians agree is inaccurate. But when it comes to Poles’ participation in the atrocities of World War II, there is less consensus about what transpired—a reflection, perhaps, of the complexity of the period under debate.

Earlier this year, Polish president Andrzej Duda said he would not allow the country to be “vilified” by “false accusations,” the Associated Pressreports. But critics say a blanket ban on discussing Poland’s role in the Holocaust risks quashing academic inquiry and further blurring the historical truth. “This is all about nationalism, really, and about the imposition of a nationalist historical narrative,” Rafal Pankowski, a political scientist and head of NEVER AGAIN, a watchdog organization that fights anti-Semitism, toldThe Washington Post.

It’s no surprise that Poland—a country scarred by hundreds of years of partition, occupation, violence and suffering—still debates historical representation. Duda insists that signing the law will make the world aware of how Poland views its own history, calling it “a signal that the Polish state sees a problem that hurts [us].” “The point is not to punish anyone,” he said.

But critics are concerned that a law seemingly intended to quash debate will stoke Holocaust denial instead—an outcome that could hurt more than the feelings of the Polish state.