At the end of March, the historian Jan Grabowski was set to have a busy few weeks. First came the release of what he describes as “the most important” of his 17 books, which features his research into the Polish policemen responsible for the deaths of hundreds of thousands of Polish Jews during the Holocaust. A week later, a hearing was set to take place in Warsaw in a lawsuit he filed against a nationalist organization aligned with Poland’s ruling Law and Justice Party, over its claim that he “falsifies the history of Poland” by doing that work.

That hearing has been postponed indefinitely because of the pandemic, but the issues it raises are not going away anytime soon. “I have no doubts of course my detractors will strike sometime soon because that’s what they do. It’s a question of time,” he tells TIME by phone while in lockdown in Warsaw. “Whenever I write about something that speaks to the fact that segments of Polish society during the war were complicit with the Holocaust, I become an enemy of the people.”

Europe’s physical battles of World War II ended 75 years ago with German surrender on May 7, 1945. But that doesn’t mean the fighting is over: A wave of right-wing nationalist leaders, who have come to power in Europe in recent years, are waging a war of words over the past. While outright Holocaust denial remains an issue, says scholar Deborah Lipstadt, author of Denying the Holocaust: The Growing Assault on Truth and Memory, these days there’s more “rewriting the history, taking inconvenient details and reshaping them.”

So, as historians like Grabowski, 58, try to tell the story of what happened all those decades ago, they’re facing resistance from officials who have their own reasons for wanting to tell the story a certain way—and, they say, the outcome could affect the lessons the world takes from World War II for generations to come.