At the end of January, 73 years after Soviet troops marched through the gruesome gates of Auschwitz, Polish lawmakers advanced a bill that would make it a crime to blame Poland for the Nazi death camps and other German atrocities committed within the country during World War II. If the measure becomes law, uttering the phrase “Polish concentration camp” could result in a fine or even prison.

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The move is being pushed by the country’s ruling right-wing Law and Justice Party and President Andrzej Duda said Tuesday he would sign the measure. His promise to submit it for further constitutional review did little to quell the outcry from historians and the Israeli government that Poland was whitewashing history. Many critics used one word to counter the notion that Poles were merely bystanders to the Nazi’s murderous mission: Jedwabne.

Here’s what they mean.

In the summer of 1941, the small Eastern village of Jedwabne was occupied, as was all of Poland, by a contingent of German police. On a blistering July day, a group of Polish men from in and around the town began rounding up Jewish male residents. The Jews, led by the local rabbi, were forced to pull down a statue of Lenin that was left over from the Soviet occupation of the region. Then, with the Germans looking on, they were taken to a barn and clubbed and stabbed to death by their fellow townsmen.

“It was a peasant community using their own rudimentary tools,” said Jan Gross, a professor emeritus of history at Princeton. “They wanted to use firearms but the Germans wouldn’t let them touch them.”

The carnage didn’t end there. The raids widened as the day wore on. More and more Jews of both sexes and all ages were packed in the barn. With a crowd of townspeople and German police looking on, the structure was set alight. The next morning a grisly pile of burned and asphyxiated corpses lay amid the smoldering ruins.

Of those basic facts, there is little dispute. About everything else, there has been a raging debate. A memorial stone placed the number killed at 1,600. A partial exhumation of the site decades later, which was strictly limited to avoid defiling the site, produced estimates of 300 to 400 victims.

But the hottest controversy has centered on raw questions of complicity versus compulsion: Were the locals of Jedwabne compelled to kill or were they instigators of a mass murder? Poland was under brutal Nazi control at the time. Auschwitz, 300 miles to the south, was holding Polish political prisoners; it would become a killing factory of the Final Solution within a few months.

The Nazis certainly set the conditions for the extermination of Jedwabne’s Jews, and the Germans in the town could have stopped the massacre at any time. But many scholars say the record amassed during numerous postwar trials and a three-year investigation by a national commission is clear that the massacre amounted to the willing murder of Poles by Poles.

Gross, who was born in Warsaw and has written extensively about anti-Semitism in Poland, put it starkly in “Neighbors,” his seminal 2001 history of the Jedwabne pogrom: “One day, in July 1941, half of the population of a small East European town murdered the other half.”

Other scholars and, increasingly, Polish nationalists have pushed back hard on scholars and politicians who have held the townspeople responsible, arguing that Poles shouldn’t be blamed for an atrocity that happened under the gaze of armed occupiers. They contend some of the confessions of locals were coerced, and that the efforts of some Poles to safeguard Jews at Jedwabne were ignored.

As right-wing factions have gained influence — and eventually a governing majority — the denials of complicity have grown louder. A memorial stone in the village was defaced with swastikas in 2011. In 2016, Education Minister Anna Zalewska, speaking around the anniversary of killings, dismissed the idea of Poles burning Jews in a barn as “a matter of opinion,” leading to calls for her firing.

Zalewska remains in office and is member of the Parliament that is one step closer to making such opinions illegal.