The murder of satire is no laughing matter. The horrifying carnage at Charlie Hebdo is a reminder, if ever we needed one, that irreverence is the lifeblood of freedom.
I suppose it is some sort of backhanded compliment that the monsters behind the slaughter are so fearful of the lance of mirth that the only voice they have to muffle it is the sound of bullets. Magazines such as Charlie Hebdo are in the business of taking liberties, even outrageous ones, but they exist so that we never take the gift of disrespect for granted.
Liberty and laughter have been twinned in the European tradition for more than three centuries and have together proclaimed as precious the right to ridicule.
Graphic satire first arose as a weapon in the atrocious and prolonged religious wars that divided Catholics and Protestants.
For Protestants, the printing press was the answer to the imagery of the Roman church by which, as they saw it, heretics and sceptics were brought to book.
So they invented an anti-iconography in which popes were turned into fantastic monsters, and kings into ministers of slaughter. The Dutch, who invented the illustrated news gazette in the middle of the 17th century, saw themselves as the victims of religious fury.
Their graphic counter-attack began with popular illustrated histories of their rebellion against the Spanish monarchy - with the Duke of Alva their favourite bogeyman. It broadened into a regular weapon of partisan polemics inside the republic as well as against foreign threats to "Holland's Freedom".
The first great modern graphic satirist was Romeyn de Hooghe, enlisted by William III at the end of the 17th century in his relentless war to the death with Louis XIV.
De Hooghe obliged with sprawling cartoons representing the wars against the French monarch and his allies as a battle between liberty and religious despotism. The satirists again saw themselves leading the cavalry charge against the bigots.
And it was in the interests of the Protestant states to let them off the leash.
The golden age of "no-holds-barred" graphic satire in the 18th century arose on the tomb of religious warfare. But it was also made possible, in Britain especially, by the space opened when no one political force or institution could command a monopoly of power.
Though the Whigs dominated government for much of the century, it was never to the total exclusion of opposition, and, as with all oligarchies, factions arose, each of which turned to the caricaturists to puncture the pretensions of their enemies, expose their hypocrisies, and bring down the mighty in a gale of scornful hilarity.
Thus it fell to the British to reinvent politics as comedy, and they went at it, on stage and in print, with a ferocious energy that has never been surpassed.
Even now in the United States, the enemy of democracy - after the poison of money - is reverence; with satire penned into the safe fold of late-night television.
But in the great age of graphic-attack politics, there was nowhere to run to, and no great institution or person was safe from the barbs of comedy.
The Church of England; dissenters such as the Methodists; the Bank of England; leading politicians and the royal family itself were all fair game.
Satire became the oxygen of politics, ventilating healthy howls of derision in coffee houses and taverns where caricatures circulated every day and every week. James Gillray, the greatest of all the caricaturists, was in such demand that Hannah Humphrey, his publisher, would rent out entire albums of his choicest items for a night's or a weekend's entertainment.
Good fun was to be had by all perusing images: a grossly bloated Prince of Wales recovering from a night's dissipation; William Pitt, prime minister, as a toadstool growing out of a dunghill; or a cartoon of Queen Charlotte, pendulous breasts nakedly exposed, holding at bay the prime minister and the Lord Chancellor.
Gillray was arrested only once - for a cartoon of politicians kissing the bottom of a royal newborn - and never imprisoned. Whatever the liberties he took, no harm befell him. The great tradition of ridicule passed to heirs in Britain, then to America and Europe: to Honore Daumier and George Cruikshank; the begetters of Krokodil and Private Eye, Spitting Image and Canard Enchaine as well as Charlie Hebdo.
On Wednesday, there was a bloody attempt to wipe the smile from our faces. But though the self-righteous have killed the satirists, they will never annihilate satire itself. Just the opposite. From now on, Charlie Hebdo will be the rallying point for all those who cherish life and laughter over the death cult of sanctimonious gloom.
So we owe it to the fallen to remind ourselves, amid the blood, grief and rage, that just because the unhinged perpetrators are murderers, does not mean they are also not clowns.
THE FINANCIAL TIMES