Poland’s Senate passed a controversial bill on Thursday that outlaws blaming Poland for any crimes committed during the Holocaust.

The bill was proposed by the country’s ruling Law and Justice party (PiS) and calls for up to three years in prison or a fine for accusing the Polish state or people of involvement or responsibility for the Nazi occupation during World War II. The proposed legislation has raised concerns among critics about how the Polish state will decide what it considers to be facts. Lawmakers in Israel have pointed to historical records citing complicity by some Poles in the activities of the Nazi regime. Israeli Prime Minister Benjamin Netanyahu called it an “attempt to rewrite history.”

Early Thursday morning, senators voted 57 to 23 for the bill, with two abstentions. The proposal requires approval by President Andrzej Duda, who supports it, to become law. “We have to send a clear signal to the world that we won’t allow for Poland to continue being insulted,” Patryk Jaki, a deputy justice minister, told reporters in parliament.

Here’s what you need to know.

What exactly would the law make illegal in Poland?

The legislation criminalizes any mention of Poles “being responsible or complicit in the Nazi crimes committed by the Third German Reich.” The harshest penalties are reserved for those who refer to Nazi-era concentration camps such as Auschwitz as “Polish death camps.” Only scientific research into the war and artistic work are exempted.

The use of the term “Polish death camp” has riled both the current nationalist government and its more liberal predecessors. According to Polish politician Jan Grabiec, the Polish foreign ministry issued 913 statements between 2008 and 2015 in response to the term being mentioned.

Former U.S. President Barack Obama caused an uproar in Poland when he used the phrase “Polish death camp” while posthumously bestowing a Presidential Medal of Freedom in 2012 to Jan Karski, a Polish World War II resistance fighter. Obama apologized for using the phrase after being denounced by current European Council President Donald Tusk, who was then the Prime Minister of Poland.

Why has the proposed law become a diplomatic incident?

The bill sparked outrage in Israel after it passed through Poland’s parliament on Jan. 26, on the eve of Holocaust Remembrance Day. Many in Israel call it an attempt to whitewash the role some Poles had in the detention and killing of around three million Polish Jews during World War II.

“The legislation will not help further the exposure of historical truth and may harm freedom of research, as well as prevent discussion of the historical message and legacy of World War II,” Israel’s Foreign Ministry said in a statement. The bill was passed despite assurances from Poland that there would be a dialogue with Israel before the vote took place.

The U.S. State Department also warned Polish lawmakers against passing the bill, saying it could have “repercussion” on the country’s “strategic interests and relationships, including with the United States.”

What does the historical record say?

Poland was attacked and occupied in 1939 by Nazi Germany, which led to the building of concentration camps, including Treblinka and Auschwitz, that were operated by the Germans. The Germans killed about 1.9 million non-Jewish civilians and about three million Jews during the occupation of Poland, according to the U.S. Holocaust Memorial Museum. A number of Poles risked their lives to help hide Jews, according to the POLIN Museum of the History of Polish Jews.

But like certain citizens of other nations occupied by Nazi Germany, some Poles were complicit in the Nazi atrocities. According to the POLIN museum, a small minority of Poles either extorted money from Jews hiding from the Germans or outed them. The Nazis also recruited local collaborators to round up Jews for the camps. In addition, there were anti-Semitic pogroms during and after the war. The most infamous happened in 1941 in the town of Jedwabne, in which 400 Jews were set on fire in a barn by their neighbors.

The Polish prime minister tweeted a metaphor on Sunday intended to put these activities in context. Morawiecki wrote: “A gang of professional thugs enters a two-family house. They kill the first family almost entirely. They kill the parents of the second, torturing the kids. They loot and raze the house. Could one, in good conscience, say that the second family is guilty for the murder of the first?”

Why Poland is doing this now?

Critics have accused the right-wing government of using the issue to bolster political support. PiS has been accused of pandering to nationalists and the far-right through xenophobic language and tailoring its message to appeal to a spectrum of right-wing voters. PiS’s leader Jaroslaw Kaczynski once said Muslim refugees carried “various parasites and protozoa” and the government’s education minister in 2016 discounted two well-documented massacres of Jews, including Jedwabne, by calling it a matter of “opinion, ” according to the Times of Israel.

There has been a resurgence of far-right sentiment in the country. A Polish government pollster found in a November survey that more than one in three polled said they supported far-right activities. That same month, far-right nationalists marched in Warsaw, brandishing slogans and signs that said “Clean Blood,” “White Europe, and “Europe Will Be White.” Foreign Minister Witold Waszczykowski said the march wad fueled by “patriotic behavior of Poles” and displays of xenophobia were “incidents” that were “of course, reprehensible.”

Read more: It’s Almost Impossible To Get An Abortion In Poland. These Women Crossed The Border To Germany For Help

The government denies the bill was intended to limit free expression or rewrite history, but critics say otherwise. Yad Vashem, the World Holocaust Remembrance Center in Israel, agreed that the term “Polish death camps” was a historical misrepresentation in a statement late last month. “However, restrictions on statements by scholars and others regarding the Polish people’s direct or indirect complicity with the crimes committed on their land during the Holocaust are a serious distortion” the statement read.

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