The despicable terrorist attack in Norway has raised the question of whether free speech can lead to murder, and if so whether more should be done to restrict hate speech on the Internet and elsewhere. Once again, terrorism is threatening not only the security of citizens, but also their most cherished freedoms, and those most essential to addressing moral and social challenges.

The head of the Social Democratic party in Germany, Sigmar Gabriel, stated that “xenophobia and nationalism in the region fostered the attacks in Norway” and that “the center of society has to make clear that there is no room for this with us, even for sanitized versions.” Thorbjørn Jagland, former prime minister of Norway and current chairman of the Nobel Peace Prize Committee, warned politicians — citing specifically Britain’s David Cameron — “to be very careful how we are discussing these issues, what words are used . . . the words we are using are very important because it can lead to much more.”

These arguments are consistent with a pan-European consensus — largely unchallenged — on the necessity of adopting hate-speech laws criminalizing certain ways of speaking about ethnic or religious matters. A principal argument in favor of hate-speech laws is that, in multicultural societies, unguarded speech leads to hate crimes against vulnerable minorities, or even the resurgence of totalitarianism and genocide. But this argument is difficult to reconcile with reality.

In Scandinavia, Denmark is famous (infamous to some) for having a much freer and often fierce debate (notwithstanding an actively enforced hate-speech prohibition) about immigration, Islam, and multiculturalism than Norway and Sweden. Yet it was in Norway that Anders Breivik wantonly murdered more than 70 people. While official Sweden boasts of its commitment to tolerance, the country has experienced a number of violent crimes committed by right-wing extremists in the last 20 years, including two separate instances of gunmen targeting innocent immigrants, as well as the assassination of a left-wing trade-union official. Denmark, on the other hand, has experienced very little politically motivated violence, and most of it has been committed by left-wing extremists.

The best way of demonstrating the lack of any apparent causal effect between hate speech and violence is to compare statistics on hate crimes in Europe, where all countries have hate-speech laws, and in the United States, where the First Amendment protects even hate speech.

Using the logic of Gabriel and Jagland, hate crimes should be widespread in the U.S. and retreating in Europe. This, however, is not the case. While differences in methodology render it impossible to make direct comparisons between the statistics on hate crimes in the U.S. and in the EU member states, the discernible trends do not suggest that hate crimes are reduced by hate-speech laws.

From 1996 to 2009, according to FBI statistics, the U.S. saw a per capita decrease of reported hate crimes of 33.84 percent, and 2009 saw the lowest number of reported hate crimes since 1996. In the European Union, the picture is quite different. Despite fluctuating numbers during the period from 2000 to 2008, the general trend, according to the EU, is an increase in hate crimes in eleven of the twelve EU countries that collect sufficient data to make a judgment. This includes countries such as Belgium, the United Kingdom, and Germany, which has some of harshest hate-speech laws in Europe.

As for the resurgence of totalitarianism and genocide, it is often forgotten that in Weimar Germany several leading Nazis were convicted for anti-Semitic writings under a blasphemy law. This did nothing to avert the tragedy of the Holocaust. Similarly, in the Federal Socialist Republic of Yugoslavia hate speech was punishable with up to ten years’ imprisonment. However, these laws were mostly used to choke criticism of the socialist dictatorship and clearly did not reduce animosities among ethnic groups, as witnessed by the crimes against humanity that took place in the Balkans with the breakup of Yugoslavia.

Moreover, if words in themselves are dangerous, European politicians should target not only right-wing blogs but also the Koran, as has been illiberally proposed by Dutch politician Geert Wilders. It is after all indisputable that Islamists from New York to London to Mumbai have justified the killing of thousands of innocent people with reference to their faith. Yet free societies do not ban the Koran, and most Muslims are able to reconcile the intolerant parts of the Koran with respect for others’ right to life.

Neither the statistics on hate crimes nor European history offers any compelling reason for criminalizing hate speech. That does not mean that hatred and extremism should be left unchallenged. Indeed we have an obligation to confront extremism in all its forms. But that obligation is a moral one, not a legal one. It is up to all of us, as individuals and as groups in civil society, to defeat extremism and radicalization before it results in new Anders Breiviks. And our ability to do so will be severely weakened if we limit freedom of expression — the very right that allows us to sound the alarm.

— Jacob Mchangama is director of legal affairs at the Danish think tank CEPOS and external lecturer in international human-rights law at the University of Copenhagen.