The writing was on the wall. European streets in general and French ones in particular are turning into a battlefield of radical, extremist Islamist zealotry.

The battle is an extension of the Middle East front lines.

Not that anyone should have been surprised. The first wave was carried for several years after 9/11 in 2001 by al-Qaida sympathizers and supporters, who pursued their ideology of global jihad in impressive terrorist attacks in Madrid, London and Istanbul.

After a relative calm that created the illusion that Europe was relatively safe came the second, current wave. It reflects the rise of Islamic State and the weakening of al-Qaida.

There are numerous bloody indications that Islamic State and al-Qaida are back in action on European soil. A soldier was stabbed to death in London; gunman stormed a synagogue in Toulouse.

Another gunman killed two Israeli tourists in the Jewish Museum in Brussels.

Two characteristics are commonly found in most of these terrorist incidents. One is that some attacks have been carried by young, local Muslims who were inspired by Islamic State or al-Qaida. The second is that some terrorist incidents are perpetrated by young European nationals who volunteered to fight in Syria and Iraq and came home after acquiring battlefield experience and being thoroughly brainwashed.

There are thousands of European nationals fighting in Syria and Iraq who have become a major headache to the various European security services. This phenomenon is particularly widespread in France, which houses the largest and potentially the most violent Muslim community.

French Intelligence estimates that between 700 and 1,000 French volunteers are fighting alongside Islamic State and al-Qaida.

Because of that, the shootout Wednesday in central Paris in broad daylight is a clear indication of the failure of the French police and security services. Charlie Hebdo’s offices were guarded by the police, because everyone knew it was a target on numerous occasions in the past and may well be so in the present and future because of its satirical mockery in writing and cartoons of Islam in general and the Prophet Muhammad in particular.

And yet the three gunmen managed to kill the police guards and nearly a dozen of the magazine’s writers and cartoonists and to flee unhurt.

It was a sad irony that, minutes before the attack, Charlie Hebdo’s Twitter published a cartoon wishing a Happy New Year “and particularly good health” to Abu Bakr al-Baghdadi, the leader of Islamic State .

The attack carried the pattern of targeted killing. The terrorists had a clear plan, knew what they wanted to achieve, and acted calmly – as the graphic footage of the cold-blooded execution of one of the wounded and helpless police guards shows.

No doubt they were professional killers.

On Wednesday night, al-Qaida Yemen claimed responsibility for the attack. But regardless of who was behind it – al-Qaida, Islamic State foreigners or a local Muslim cell, it is a direct challenge to French and Western democracy and to the fundamental values of liberty and freedom of expression.

The West is slowly realizing that this is a clash of civilizations.

It is a war declared by Muslim fanatics against what France and Europe treasure and stand for. The answer has to be accordingly – better cooperation between Western security services, better intelligence on the terrorist groups, and new laws that would limit the ability of the enemy to exploit and take advantage of democratic values.

The Paris massacre is France’s 9/11 – and à la guerre comme à la guerre.