Three gunmen broke into the headquarters of French satirical newspaper Charlie Hebdo yesterday and murdered 12. The attack is almost certainly revenge for the paper’s decision to publish cartoons depicting the Prophet Muhammed and Muslims; its offices had previously been firebombed, and the gunmen identified themselves as members of Al Qaeda.And now the deluge: France has plunged into mourning, law enforcement still searches for the perpetrators and revenge attacks against the country’s Muslim community have already begun. Global outrage has coalesced around a shared commitment to the principles of freedom of speech and press. In any free society, it is understood that there is no right to live free of offense. There should be no laws prohibiting the press (or individuals, for that matter) from criticizing, ridiculing, satirizing or mocking any religion or philosophy.The paper has also been criticized for its decision to depict Jews and Muslims with stereotypical Semitic features in a manner some have identified as racist. But there is a way to deal with this: It's with debate, not bullets.

There’s also quite a gulf between acknowledging that fact, and arguing, as the Catholic League’s William Donohue has done, that the paper’s editors brought their deaths upon themselves.“Killing in response to insult, no matter how gross, must be unequivocally condemned. That is why what happened in Paris cannot be tolerated. But neither should we tolerate the kind of intolerance that provoked this violent reaction,” he said in a public statement. Of Stephen Charbonnier, who worked in the paper's editorial department and perished in the shootings, Donohue actually went on to say that it was “too bad that he didn’t understand the role he played in his tragic death.”Donohue is angry because Charlie Hebdo has also printed cartoons lampooning the pope and the Catholic Church. Again, the way to deal with this is to condemn it. Asserting that cold-blooded killers had a right to be angry (which implies that their murderous reaction is somehow understandable)  totally misses the point.

Donohue, by the way, is hardly a free speech champion. The Catholic League’s definition of anti-Catholic persecution can be roughly defined as “any public criticism whatsoever of the Catholic church.” He’s infamous for protesting films like Dogma and The Golden Compass for their perceived promotion of atheism and anti-Catholic sentiment.

If Donohue had his way, U.S. law would severely restrict criticism of religion, if not ban it altogether. To ideologues like Donohue, the First Amendment and its guarantee of separation of church and state is an obstacle rather than a democratic principle to be celebrated.There is a line between criticizing art and demanding retribution for its very existence.The balance between these two camps is at the heart of free speech as it is understood in the United States and elsewhere. Creating art – no matter what sort of art it is – should not be a capital offense. Cartoonists and indeed all other media professionals should be able to go to work and publish without needing to hire security guards to protect themselves and their families.

Yesterday’s assault on Charlie Hebdo was unquestionably an attack on free expression, in more than one sense. It didn’t take long for outraged individuals to launch reprisal attacks on mosques and a Muslim-owned restaurant. French political observers have also theorized that the tragedy may have a silver lining for the country’s resurgent far-right, headed by Marine Le Pen.

Le Pen, a devout Catholic, mixes social conservativism with nationalism in a manner familiar to anyone who watches the American Religious Right. This attack on free expression led to another and now may eventually lead to even more, illustrating how fragile, and how necessary, the principle really is.

So today we acknowledge our rights, and understand how important they are – and how easily they can still be undermined by religious extremism.