In Friday’s Wall Street Journal, the German newspaper editor Josef Joffe contributes an intriguing if somewhat ungainly little essay; its subject is the mosque in Hamburg where Mohamed Atta and other September 11th conspirators plotted their treachery. German authorities recently shut it down. One of its jihadist preachers was finally tried and imprisoned. “This is where Imam Muhammad al-Fazazi used to preach venom and murder throughout the 1990s, opining that ‘Christians and Jews should have their throats cut.’ In 2003, a Spanish court gave this pious cleric 30 years for planning attacks on Jewish institutions in Morocco.”

Mosques have become controversial in the West. To elite liberals, this is cause for dismay and anger, and evidence of the derangement of the Western mind. More sympathetic consideration would disclose that certain striking events — for instance one in Lower Manhattan on a fine September morning — may possibly have left an impression on Western observers.

Mr. Joffe continues:

Meanwhile, a naturalized German from Syria, Mamoun Darkanzanli, had taken the pulpit [at the Hamburg mosque]. Investigators call Darkanzanli the “elder statesman of jihad” and have a fat file on him. They think that he is bin Laden’s man in Germany, and that he also helped the Madrid train bombers of 2004. When Spain asked for his extradition, the German Constitutional Court said “nein.” That would violate his rights as a German citizen.

Darkanzanli continues to live in Hamburg — unmolested and on welfare. And he knows his rights, wrapping himself in the constitution while preaching that Allah will kill the infidels. He isn’t inciting violence, just spreading God’s word. This is a problem that stumps counterterrorism officials around the Western world.

Why this should be such a stumper is something of an enigma. Mr. Joffe makes little effort to unlock it. On the contrary, he simply presupposes that current orthodoxy on Free Speech stands invincible.

Fanaticism itself is no crime, nor is discoursing on Allah’s will. As in the U.S., a hateful ideology is no ticket to prison. Authoritarians have no qualms about equating ideology and intention. But Western liberal democracy obeys due process and the concept of “innocent until proven guilty.” Words, as Oliver Wendell Holmes famously wrote for the Supreme Court in 1919, have to “create a clear and present danger” to be criminal. In that respect, the Germans may have become more American than the Americans.

But of course it is illegal in Germany to deny the Holocaust; in numerous Western nations speech codes on sensitive matters, when contravened, can indeed result in a “ticket to prison”; in the UK Christian preachers have been prosecuted for denouncing homosexuality; Canada’s most famous commentator narrowly escaped legal sanction at the hands of that country’s Human Rights Commission — precisely for his criticism of Islam.

Thoughtful observers like Mr. Joffe would do well to take cognizance of such incidents. In totality they would seem to lay to waste the common presupposition on Free Speech orthodoxy. The truth is that for our liberals Tolerance is a one-way street. Far from invincible, Free Speech is abandoned for the pretense it is the moment a stronger force intrudes on it. And stronger forces are plentiful in our politics: genuine Free Speech men, ready to make good on Voltaire’s famous dictum, are few and far between.

What is more alarming is that in some cases this phony orthodoxy is permitted to protect and succor Jihadists but not their critics. Darkanzanli can lounge in the plenty of the European welfare state and counsel his followers to bring doom and slaughter to the infidels, while Mark Steyn must mount a lengthy and costly defense against charges of hate speech.

More alarming still is the deeper disorder of the liberal mind, which can maintain its self-righteousness in the teeth of all this manifest blunder and incoherence. Proud liberals have spent several weeks now preening their indignation at the very thought that Americans would oppose the construction of a mosque at Ground Zero in New York. The Mayor of New York feels at liberty to conjecture, without a shred of evidence, that a man who attempted to detonate a bomb in Times Square was a disgruntled opponent of the new health care bill; and then, some time later, to read us all a series of scolding lectures on tolerance when he discovers firm opposition to the Ground Zero Mosque. The imposture is transparent. The Mayor does not scruple to impute malice and treason to his countrymen with both his ignorant speculations and his lectures on tolerance.

Our age is not noted for its historical imagination. The sheer antiquity of the Jihad is lost on most of our contemporaries. Some suppose it began in the wastes of Afghanistan in the 1980s, armed by Reagan and the neocons; others would prefer to imagine that it grew out of the early 20th century totalitarian systems; still others conceive that it was borne out of Israeli perfidy and oppression.

In truth the Jihad is older than almost anything around. It outlasted empires Roman, Byzantine, Frankish, Spanish and more. When King Alfred was fighting the Danes it was carving up the enervated Byzantine provinces of the Near East. After its initial surge across from Arabia to Spain — in which it extinguished almost without a trace the Latin civilization of North Africa — petered out, it was successively reinvigorated by the conversion of Asiatic tribes, culminating in the Ottoman Turks and their fearsome empire. Only during the Crusading Age was a sustained counterattack mounted; and nothing is more embarrassing to liberals than the Crusades.

So we do well to recall that the Jihad is very old. There is little reason for confidence that its current material weakness will endure. It excels at harnessing the resources of the conquered and subjugated. Its creed will always appeal to the resentful and discontented, to criminals, radicals and brigands. For centuries the ranks of its Mediterranean pirates were reinforced by Greek and Italian renegades. It is strong in our prisons today.

The Jihad has outlived archaic despotism, feudalism, monarchy, republicanism and nationalism; and it is not too much to speculate that it will live through the eclipse liberal democracy as well.