The conviction of the fanatical preacher Anjem Choudary is a welcome milestone in the long and torturous process of countering Islamic extremism in Britain.
If, when the cleric is sentenced, he is given years behind bars then he will be richly deserving of such a fate given the bloodshed and heartbreak to which he has determinedly contributed.
And yet I struggle to celebrate his conviction for inviting support for a proscribed organisation, because despicable hate mongers like him have triggered a necessary but major inroads into freedom of speech.
They have made our societies less trusting and less at liberty, and have done so by deliberately creating a situation where the authorities respond with such curbs.
In many respects the world is a better place than it has ever been. Hundreds of millions of people around the globe are being lifted out of disease and poverty. Billions of people can now expect to live well into old age.
By many measures there is less violence in most societies than there has been for centuries, perhaps ever.
But freedom and prosperity is bringing its own problems, one of which is a tier of people who despise western values and freedoms and are willing to see many civilians slaughtered in their bid to annihilate our lifestyles.
Choudary is one such man. No doubt a forensic psychologist would have much to say about a person who drank heavily and had casual sex at university but who became a chief propagandist for a group as brutally repressive as Islamic State.
IS is one of the most depraved organisations in modern history. It not only kills civilians for ‘offences’ such as adultery and homosexuality, it glories in making their deaths painful and public and has distributed slick videos of such horrors.
Clearly the recent military defeat of these fiends in Manbij in Syria and Sirte in Libya should be the source of international celebration.
But in the West men such as Choudary have done something that is so calculating and so repulsive that it could without hyperbole be classified as evil.
They have pushed the freedoms of liberal democracies right to the limit in a bid to destroy – not just to damage or constrain or reform, but to destroy – those liberal democracies.
They spread the message as explicitly as they can without going outside the law (which is why the law has been changed through terror legislation). Meanwhile the people for whom they propagandise, the godfathers and foot soldiers, would, if they could, use nuclear weapons to take out whole cities.
Only hopelessly naive people fail to grasp this. In a humiliating but appropriate display of public insubordination, Jeremy Corbyn was contradicted by his own shadow cabinet in his refusal to agree wholeheartedly with the appropriateness of shooting dead hostage takers in a Bataclan theatre-style situation in which fanatics are killing hostages.
Wicked people pushing the law to the limits has of course been a facet of human life since the very first laws. Dedicated criminals have done it for centuries.
Terrorists in Northern Ireland did it through the Troubles, covering their tracks so carefully that they were routinely acquitted of murders for which they were plainly guilty but which could not be proven beyond a reasonable doubt.
But what do you do about people who just use words?
You can prosecute them if they incite hatred but if a lower threshold for prosecution is set then you soon run into problems – consider the court case last year against Pastor Jim McConnell.
It must not be forgotten that he was prosecuted following a complaint to police by an Islamic activist in Belfast who had praised the ‘peace’ brought about in Mosul by mass murdering IS.
Despite an apology, the complainant’s remark was certainly worse than anything Pastor McConnell said. But praising IS should attract contempt, not charges.
The man who praised Mosul peace was the later target of abuse from a woman who said that Muslims should be gassed. Now that should be an offence and she was last week given a suspended sentence. Likewise, George Seawright was the deserved recipient of a suspended sentence for saying in 1984 that Catholics should be incinerated.
But isolated shameful comments are one thing. Countless people have said things in a rage which they later regret bitterly.
It is a different matter when someone engages in the sustained promotion of something such as damaging as jihad over many years.
David Anderson QC, the independent reviewer of terror legislation, told BBC Radio Four after Choudary’s conviction that “it is difficult to craft a law that can clearly distinguish people who are dangerous from people who are merely revolting”.
Amid repeated attacks on civilians, it is a balance we have to keep striving to find.
Ben Lowry (@BenLowry2) is News Letter deputy editor