The Copenhagen shooter probably modeled his attacks on those in Paris, the Danish police quickly concluded. There is supposedly a three-fold similarity to the shootings which took place in January at Charlie Hebdo and at a Jewish supermarket shortly afterward: First the attack on freedom of speech, then against Jewish citizens and, ultimately, the final shootout with the police. The security authorities in Europe are reacting nervously, politicians are reassuring each other of assistance and support, and the Danish prime minister is swearing to fight against all who want to attack the free and open Danish society. The overall feeling, however, is a certain helplessness. And when, shortly after the Copenhagen shootings, a Carnival parade in Braunschweig is cancelled, is it because of fear and anxiety? Or was there concrete evidence of a planned attack?

No compromise on civil liberties

Despite all justified caution, even if the police actually have concrete evidence, we cannot let our daily lives be restricted by Islamists who are waging a war on our civil society, our customs and our way of life. In principle, after each of these attacks, a call must prevail in defense of freedom of speech, the same call heard at the impressive demonstration in Paris: "We are not afraid." That is admittedly not so simple, but those who allow themselves to be ruled by fear in these circumstances have already lost.

And every attempt - whether with another blasphemy ban or similar offers for a compromise - has failed to calm the tempers of certain Muslims. Indeed, what would come after this first step? In various European cities there have already been reports of self-styled guardians of public morality, who harass and threaten girls in short skirts and guys who go out partying. What's next? A headscarf requirement for women?

Dealing with radical Islam openly and critically

Our societies in Europe will never conform to the requirements of Wahhabism or other extreme sects of Islam - and they shouldn't, not at any price and under no circumstances. But in order to make that clear, the debate with them needs to be conducted more openly and critically. And it doesn't help us to get into theological debates about the relative warring side of Christianity, Islam or other world religions. The recent attacks and the generally aggressive tenor against those of other faiths emanating from a radical wing of Islam cannot be explained away by referring to the murderous brutality of the Crusades or the excesses of the Spanish inquisition.

Another line of argument that can also no longer stand is when the majority of peace-loving Muslims say they don't need to concern themselves with the extremism of a minority. Under the circumstances, there is nothing left for them to do but to actively address the hardliners and violent members of their own religion. A political and theological debate within Islam over the development of the religion in the 21st century and its relation to history and tradition is long overdue.

And furthermore, we Europeans should also have the courage to openly lead the political debate in this context, using our legal system as the basis. Freedom of speech, separation of church and state, and gender equality are not negotiable. The clash between modern liberal values and Islam, which does not distinguish between public law and private faith is a real contradiction and cannot be kept quiet. Freedom of dissenting opinion is an achievement that we must defend, since it creates the space in which every man can pursue happiness - as a Christian, Muslim, Jew, Hindu, atheist or a follower of another spiritual idea.

The constitution applies to all

No Muslim in our midst may impose their conception of earthly and eternal life or their customs and traditions on followers of other faiths. At the same time, they enjoy the freedom to practice their religion here, a right that is no longer protected in many Islamic countries. The basis for coexistence in Germany is the constitution. Since everything needed is contained within, and it applies, without exception, to everyone who lives within its scope. The Danish prime minister is right: We need to fend off those who want to attack our open, free societies.