Charlie Hebdo asks for trouble, and they get it. Yesterday they got it in spades. They risk big, they get a lot of attention, and it appears they exceeded the French state’s ability to protect them. The murderers they incited have been caught and will be punished, unless some future hostage-taking sets them free. For everyone outside al-Qaeda and the French criminal justice system there is a terrible feeling that we must do something.

We have to take great care in how we touch the bodies lying in the offices of Charlie Hebdo, though: they’re booby-trapped.

Automatic weapons fire in the streets of Paris is, of course, nothing new. In the 1970s and 1980s urban guerrillas inspired by the appalling work of Carlos Marighella got a great deal of notoriety and a certain amount of romantic attraction. They stood no chance of achieving their aims, of driving a traumatized West into their embrace; but they were beneficiaries of radical chic.

The murderers who sought to silence Charlie Hebdo, and perhaps more importantly to stop others from being disrespectful of their religion’s founder, are devoted to a different dogma. Action-directe, the Baader-Meinhof gang and the Brigate Rosse were fanatical devotees of Marxism, a religion born in the violent upheavals of the Nineteenth Century and popular with billions of the world’s population in the Twentieth and Twenty-first.

Violent Marxists kidnapped, killed and hijacked in the 1970s and 1980s, and their descendants are still kicking around here and there as menaces to public order. Their aim was to use violence against the Establishment as a means to stampede ordinary people into the arms of the terrorists themselves. They never had a chance of achieving their aims, only of causing mayhem and death in their struggle.

The Islamists who committed so many murders yesterday stand a much better chance of achieving their aims than the Reds of forty years ago. It is important, however, to understand why.

While Islamist extremists might desire to silence all criticism of Islamism, of Islam, and of Islam’s founder; and while they might achieve the aim of muting criticism; that is not what has motivated them to act. Drawings of the Prophet Muhammad are blasphemous in Islam, and insulting drawings more so; but that is only a component of a fiendish but simple trap with much more ambitious aims.

The aim of stopping people from publishing drawings of the Prophet Muhammad is a modest one. There are few occasions when most people feel the need to publish drawings of the Prophet.

The apparent aim of stopping insulting cartoons of the Prophet is achievable, at very little cost to Europeans. A Europe in which people never depict the Prophet Muhammad is not very different from the Europe of today, the Europe of fifty years ago, or even the Europe of a century ago.

The jaws of the trap are the killers’ broader aim: to provoke a global war between Muslims, including those Muslims who currently abhor extremists, and non-Muslims. Here we are at far greater risk of playing into the hands of the violent Islamists.

Islam, like Judaism, is historically uncomfortable with pictures of God, of humans (whose soul is believed to be a fragment or reflection of God), and sometimes of animals.

I respect this discomfort, and that is why I’m not making a point of displaying a picture of the Prophet Muhammad in solidarity with the Charlie Hebdo staff who were murdered yesterday or with their surviving colleagues.

When the Danish cartoons of the Prophet Muhammad were published I expressed my solidarity by buying Danish butter for a while, which was a pointless gesture, but that’s mostly what gestures of solidarity are.

In France the tricolour will stay at half-staff for three days, which is a more august way to express solidarity, but not much more productive. It’s a desperate attempt to lend some meaning to the death, and to help people deal with bereavement.

I support the right of Charlie Hebdo to be obscene, disrespectful and inflammatory; but I do not need to be obscene, disrespectful or inflammatory to be supportive. The whole point of freedom of expression isn’t for me to use someone else’s mode of expression, it’s the freedom for me to express myself in my own mode of expression.

Yet the Islamists have tempted me to do something that offends ordinary, peaceable Muslims, and that is the fiendish bit of their trap. By choosing poorly my expression of solidarity I would be taking one more step towards that great violent war between Islam and non-Islam which the Islamist bets he can win.

The Islamist is trying to stampede me and people like me into a war against Muslims and against Islam, and that is an entirely achievable goal.

There would be no winner in a war between Islam and the rest of the world: it is a war which the world need never fight and should never fight. The response of Muslims and non-Muslims to murder and violence in the streets of Paris must be to step clearly and decisively away from the war that our enemies desire.

The response of the non-radical non-Islamist people of the world to the Charlie Hebdo massacre should be the opposite of radicalism. The best response is not to seek solidarity by joining the dead in their mockery of Islam’s prophet. It is to support the countries, the systems, the freedoms and the values that make Charlie Hebdo’s blasphemous mockery lawful and possible, whatever the result.