Adolf Hitler’s notorious book is about to get a new lease on life. The copyright for Mein Kampf, which has been held for 70 years by the government of the German state of Bavaria, expires at midnight on December 31, 2015. From that moment on, any publisher interested in reprinting the Nazi leader’s virulently anti-Semitic, racist tome will be free to do so.

That realization has spawned understandable fears, especially in Germany itself, where the work has been banned since the author’s death. But in January it will be republished in the country for the first time since World War II ended, albeit in heavily annotated form. Some worry that Mein Kampf will once again be a bestseller in the lands where the Holocaust occurred, a symbolic posthumous victory for its author. At a time when anti-Semitism, racism, and xenophobia are on the rise in Europe, its republication could foment ethnic and religious hatred. The growth of militant populist right-wing parties throughout Europe, including in Germany, shows that such fears have a basis in fact.

But the history of the book, and of Hitler’s words more generally, demonstrates that there’s no clear-cut relationship between banning speech and halting the spread of ideas. The Nazi party grew despite Germany’s early efforts to curb Hitler’s speech; by the same token, today, his ideas are repudiated around the world despite being more widely accessible than ever before. The story is instructive as Europe and the United States continue to grapple with the question of how to combat newer extremist ideologies.

This is not the first time that Hitler’s words have generated public concern. Following his conviction for high treason in 1924, various German state governments barred the Nazi leader from public speaking for several years. It was during this low time in his political career that he penned Mein Kampf. The overpriced book was not an immediate bestseller; its sales dramatically increased only when the Nazi Party rose from insignificance to political prominence after 1930. By the end of 1932, close to 230,000 copies had been sold.

The Great Depression created a conducive environment for Nazi messaging. Millions of Germans cast their votes for the extremist movement, but the vast majority of them had neither read Mein Kampf nor subscribed to a Nazi newspaper. The Nazis reached huge audiences with much more appealing propaganda. Hitler the orator influenced far greater numbers than Hitler the writer. It was only after he came to power in 1933 that Mein Kampf became a staple on German bookshelves. Thereafter, Germany rapidly became a closed marketplace of ideas, where censorship and book banning ruled and anti-Semitism and racism were unassailable tenets of the new regime.

Today, Mein Kampf is available in more languages and countries than it was during the Nazi era. With only a few keystrokes one can download a copy, in any one of a variety of languages, off the Internet for free. Neo-Nazis—or ISIS fanatics, or any other extremists—haven’t had to wait until 2016 to get the text, and legal prohibitions haven’t stopped anyone from obtaining or disseminating it: If people want it, they already have it.

Moreover, the Bavarian government’s record of enforcing copyright has been spotty at best, and not due to a lack of effort. In countries where its legal authority was recognized, republication of Mein Kampf was denied. Yet in the Middle East, and even in some European countries, some publishers just thumbed their noses at German copyright law.

In the United States, Mein Kampf has never been prohibited, though some Jewish organizations opposed the sale of the book in 1933, at a time when populist demagogues were spreading their vitriolic anti-Semitism. Mein Kampf was not even banned when the United States went to war against Nazi Germany. In fact, the book’s U.S. publisher, Houghton Mifflin, urged Americans to study Mein Kampf as part of their patriotic responsibilities, and advertised it in The New York Times Book Review in 1944.

U.S. agencies analyzed the book to understand what made Hitler tick and how to best reform German society after the war. Members of the American public, too, tried to better understand the nature of the enemy by perusing Mein Kampf. In early 1939, just months before war broke out in Europe, an unabridged, critical, annotated English edition appeared in American bookshops. Libraries acquired multiple copies of Mein Kampf to feed the demand, and GIs slogged through it on military bases. Its availability did nothing to change American public opinion in favor of Nazi Germany.

However, in postwar Germany, the Allies, including the United States, took a hard line on Mein Kampf. They banned the book and made its dissemination a criminal offense. At the Yalta Conference in February 1945, Soviet, British, and American leaders had pledged “to destroy German militarism and Nazism and to ensure that Germany will never again be able to disturb the peace of the world.” To this end, Allied occupation forces dissolved and prohibited the Nazi Party and affiliated organizations and revoked Nazi laws. They also ordered the removal of all Nazi and militarist propaganda from German public life.

As part of this policy, American authorities in Germany pulped tons of Nazi literature, including Mein Kampf, to print new textbooks, newspapers, and other materials. In October 1945, American military officials staged an impressive ceremony before newsreel cameras in which the lead type used to print Mein Kampf was melted down to produce page plates for the first postwar German newspaper in the U.S. zone.

By March 1947, the cleansing of Nazi literature from German public life was so successful that Library of Congress staff complained that—despite the millions of copies of Mein Kampf that had been printed by the Nazis—they couldn’t find 150 copies for transport to American universities.

The thoroughness of the Allied purge of Hitler’s words reflects just how dangerous occupation authorities thought they were in postwar Germany. Prosecutors at the Nuremberg trials cited Hitler’s magnum opus as evidence that Germany’s leaders had conspired to commit crimes against humanity. Major F. Elwyn Jones, junior counsel for the United Kingdom, described Hitler’s book as key to understanding the Nazis’ plans for genocide: “From Mein Kampf the way leads directly to the furnaces of Auschwitz and the gas chambers of Maidanek.[sic].”

But Germany today is a very different place, and so is the world. The death and destruction caused by the Nazi regime did more to discredit Mein Kampf than any ban. In seven decades of democracy, Germans have been exposed to both Hitler’s words and Hitler’s crimes in films, print, and school. Neither the release of his unpublished second book in 1961, nor that of a mammoth edition of his collected speeches in the 1990s, triggered a major resurgence of Nazism in Germany or elsewhere.

Given Germany’s past, and the critical role the ideology expressed in Mein Kampf played in the Nazi destruction of European Jewry, vigilance is entirely appropriate. Understandably, some Holocaust survivors and organizations, such as the World Jewish Congress, have called for a continued ban on republishing the book. Germany’s Central Council of Jews has taken a different position, arguing that although the lapse of Mein Kampf ‘s copyright represents a potential danger, knowledge of the text is essential for understanding the Holocaust and National Socialism, and that the organization would not oppose the publication of the new critical, annotated edition published by Munich’s respected Institute of Contemporary History.

Sensitive to these concerns, German authorities have taken precautions to mitigate the threat when Mein Kampf’s copyright expires. Several German state officials have indicated that they will prohibit any editions designed to incite racial, ethnic, or religious hatred under the nation’s strict laws on dangerous speech.

Other German representatives believe that using selected excerpts from the critical edition of Mein Kampf will help to immunize young people from extremism. Josef Kraus, the longtime president of Germany’s teachers’ association, has pointed out that keeping silent or banning the book could have more dangerous consequences than publishing it. In today’s environment, it is better to discuss Mein Kampf openly and critically in the classroom than to have curious students seek it out on the Internet, where teachers will have no chance of influencing them.

The public debate about Mein Kampf raises a much broader question on how best to confront dangerous propaganda in today’s constantly changing information environment. With the rapid expansion of the Internet, and social media in particular, it is nearly impossible to fully suppress the spread of ideas, both good and bad. ISIS, for example, has repeatedly displayed its ability to disseminate its pernicious messages globally, even when governments or media providers take down the group’s videos or tweets. Tech-savvy extremists know how to navigate the deep labyrinths of the web to find new venues from which to transmit hate. Finding appropriate ways of addressing this problem is now the world’s collective challenge. Censorship is too feeble a weapon to defeat dangerous speech.