KRAKOW, Poland — In 1939, Poland was home to more Jews than any other nation in Europe. Partitioned by Nazi Germany and the Soviet Union that year, Poland lost a fifth of its population in World War II; 90% of Polish Jews were killed in the Holocaust. Israel was established as a Jewish homeland in 1948, out of the ashes of that global conflagration.

Poland and Israel have enjoyed full diplomatic relations since the fall of communism in 1990. But the two countries are diverging when it comes to marking the 75th anniversary of the Soviet liberation of Auschwitz-Birkenau, the most notorious of the Nazi German death camps, where more than 1 million Jews were murdered.

Politics — particularly of the nationalist kind — may be to blame.

The presidents of Lithuania and Poland, which both suffered Soviet occupation and then decades of Soviet domination during the Cold War, have withdrawn from the commemoration in Israel because of the prominent role to be played by Russian President Vladimir Putin.

In a keynote address, Putin is expected to offer his revisionist take on the war’s history that de-emphasizes the 1939 nonaggression pact signed by Nazi Germany and the Soviet Union and emphasizes the complicity of some Poles in the Holocaust.

“They want to shift the blame for unleashing World War II from the Nazis to the communists,” Putin said last month during a meeting with leaders of ex-Soviet nations in St. Petersburg, Russia, criticizing officials at the European Parliament for a resolution that blamed the pact for the war.

Putin called the Polish ambassador to Nazi Germany “a scum and an anti-Semite pig.” He has tried to partly blame Poland for the outbreak of the war.

Putin is boycotting the Polish ceremony, which will be held at the former concentration camp about an hour west of Krakow.

Poland was one of Adolf Hitler’s first victims. His armies invaded Poland in 1939 only after Germany had signed the nonaggression pact with the Soviet Union that included a secret appendix carving up Poland. The U.S.S.R. only entered the war against fascism in 1941, when Hitler broke the pact by invading it.

Though some Poles collaborated with Nazi occupiers, it’s also true that many Poles risked their lives to protect Jews.

“What’s going on right now with the fight over who should speak at the various ceremonies is a terrible tragedy, and an outcome of what happens when you politicize history,” said Deborah E. Lipstadt, a major scholar of the Holocaust who teaches history at Emory University.

She noted that politicization is going on by leaders in all three countries.

In Poland, a right-wing, nationalist government tried to make referencing Polish complicity in the Holocaust a crime, punishable by up to three years in prison. After a major outcry by the United States, Israel and other nations, Poland backed down, but it still considers such references to be a civil offense.

Lipstadt also said that Israel’s prime minister, Benjamin Netanyahu, did not do enough to push back against the Polish revisionism.

Much of central Jerusalem was on lockdown Wednesday as leaders arrived and Netanyahu and President Reuven Rivlin, the official host of the forum, began receiving guests. Israel deployed some 10,000 police officers to secure the events.

At a memorial service Thursday at Yad Vashem, the Holocaust memorial in Jerusalem, world leaders will be among those gathered to stand against anti-Semitism and genocide.

The meeting comes ahead of the official anniversary of the camp’s liberation on Monday, when the Auschwitz-Birkenau Memorial and Museum will play host to some of the same dignitaries as well as 200 Holocaust survivors — at least a quarter of them American.

Netanyahu is in the midst of a nail-biting petition for parliamentary immunity from several criminal indictments he was served with last November, which he is expected to lose in a vote next week, as he runs for a fifth consecutive term as prime minister.

Elections — the third in less than a year — will be held March 2.

Amid this political turmoil, Israel, a nation of 9 million people, is hosting a hugely elaborate event.

About 100,000 Holocaust survivors live in the country. Only 30 could be accommodated in the main ceremony at Yad Vashem, where 800 guests will attend.

Israeli media have been flooded by complaints from numerous frustrated families, who argue that survivors should have received more visibility over the big names in an unprecedented national commemoration.

In a strong symbolic gesture, Rivlin and his German counterpart, President Frank-Walter Steinmeier, will travel together from Israel to Poland, where Holocaust survivors will join dozens of heads of state.

In Poland, the World Jewish Congress, the Auschwitz-Birkenau Memorial Foundation and the Auschwitz-Birkenau Memorial and Museum have invited survivors to assemble Monday before the “gate of death” entrance to Birkenau. Ronald Lauder, the World Jewish Congress president and chairman of the memorial foundation, will address the gathering.

“This may be the last ceremony of its kind for these heroes and victims, and one of the last times they will ever be able to speak publicly about their experiences,” Lauder, a former U.S. ambassador to Austria, said in an interview. “We must bear witness for generations to come on behalf of those who will no longer be able to speak for themselves.”

Holocaust remembrances take place annually in many countries, including Israel, the United States and Poland. It’s more rare for survivors, many of whom are in their 80s and 90s, to come together across international borders.

Around 400,000 survivors are alive around the world today. In the U.S., there are about 85,000, according to the Conference on Jewish Material Claims Against Germany. The Claims Conference counts fewer than 2,000 Auschwitz survivors worldwide, about a quarter of whom live in the U.S.

“Many of the survivors of the Holocaust were in their teens when they survived. People over 35 were not surviving,” said Stephen D. Smith, executive director of the USC Shoah Foundation. “As time has gone on, you have seen more people speaking out about their experiences.”

One of those people is David Lenga, 92, who was held at Auschwitz-Birkenau as a teenager and currently lives in Woodland Hills.

Lenga, who will attend the ceremony in Poland, said he stayed away from the former prison until four years ago, when his daughter pleaded with him to show it to her. He said he believes it is his responsibility to educate others about the Holocaust.

“I can’t imagine not being there, considering the scary rise of anti-Semitism in the world. Whatever we can do to honor the memory of the dead and living — and educate people — we will do,” Lenga said.

Times staff writer Kaleem reported from Krakow and special correspondent Tarnopolsky reported from Jerusalem.