A quote from Karl Popper's work.
Karl Popper's "Paradox of Intolerance" is a powerful concept. Here are the details you requested.
Written while in exile during World War II, the book is a forceful defense of liberal democracy against totalitarianism. Popper argues that philosophies which claim to have a definitive, utopian answer for society's problems—as seen in the historicism of Plato, Hegel, and Marx—are inherently dangerous and lead to closed, authoritarian regimes. His work was a direct response to the rise of Nazism and totalitarianism, aimed at understanding and undermining the intellectual roots of such movements to prevent their recurrence.
Unlimited tolerance must lead to the disappearance of tolerance. If we extend unlimited tolerance even to those who are intolerant, if we are not prepared to defend a tolerant society against the onslaught of the intolerant, then the tolerant will be destroyed, and tolerance with them.—In this formulation, I do not imply, for instance, that we should always suppress the utterance of intolerant philosophies; as long as we can counter them by rational argument and keep them in check by public opinion, suppression would certainly be most unwise. But we should claim the right to suppress them if necessary even by force; for it may easily turn out that they are not prepared to meet us on the level of rational argument, but begin by denouncing all argument; they may forbid their followers to listen to rational argument, because it is deceptive, and teach them to answer arguments by the use of their fists or pistols. We should therefore claim, in the name of tolerance, the right not to tolerate the intolerant. We should claim that any movement preaching intolerance places itself outside the law and we should consider incitement to intolerance and persecution as criminal, in the same way as we should consider incitement to murder, or to kidnapping, or to the revival of the slave trade, as criminal.
I am writing this commentary two days after the political assassination of Charlie Kirk.
My claim is a large faction of people in contemporary liberal democracies, more pertinently the United States, have inherited and internalized "The Paradox of Intolerance", and the general mission of "The Open Society", via general civics courses in any average college and even high school.
With a fresh read of the actual original content, one can see there is a line which would prevent extreme application:
"I do not imply, for instance, that we should always suppress the utterance of intolerant philosophies; as long as we can counter them by rational argument and keep them in check by public opinion, suppression would certainly be most unwise."
The large faction of our population which cheered the death of Charlie Kirk, and the single representative of that faction which did the act of murdering Kirk, are contemporaries who have superficially internalized the mission of "The Open Society" - prevent another Hitler - with a catastrophically flawed mode: they never read the book or the paradox statement, and especially the line quoted above.
They are, metaphorically speaking, broken robots running on malformed and corrupted code. They serve the general mission of The Open Society, while omitting key caveats and subtleties.
This faction is on a drug-like high in which the slightest ripple in their orthodoxy is labelled as Hitler and Nazi.
...and their very next step in this sequence is at it's nicest is social death for that person, total exclusion. At it's meanest, very real and literal murder.
One particularly famous person of our time has uttered many many ripples in this faction's orthodoxy, and they actually migrated to a new alternative public forum (BlueSky) so as not to see his utterances, or those like him.
That same alternative platform, BlueSky, was populated with thousands of cheers of elation at the news of Charlie Kirk's death.
Let's digress further to a particular. Charlie Kirk was in performance and action doing "we can counter them by rational argument and keep them in check by public opinion". The faction that killed him and cheered Kirk's death is in performance and action "they may forbid their followers to listen to rational argument, because it is deceptive, and teach them to answer arguments by the use of their fists or pistols."
It would be nice if my dry academic survey did not contain any extremist or alarmist rhetoric. I would prefer that. Yet, in looking over the last paragraph, we see that those who "...forbid their followers to listen to rational argument, because it is deceptive, and teach them to answer arguments by the use of their fists or pistols..." have assigned themselves as Liberal, and as the last defenders of Liberal Democracy.
Since this has developed to the point of real murder, and many threats of more murder, we have no choice but to be in a state of alarm. The call to action to counter all this, it will be very difficult not formulate extremist actions.
I believe all social contexts behave like choreography. If the other dances poorly, it requires you as their partner, to dance poorly.
The faction I have just written about, they are broken robots, they are not going to deescalate, they are not going to stop. They are extremist. And real murder is central to their mode. So we are challenged with how to dance with this.
The counter needs to stop their murders. That is going require force. Understand as adults in the real world this means arrests, prisons and death penalties...at the nicest mode in a law abiding execution. The alternative is, I won't say it here. Just know this faction has to be physically stopped from the murders.
While I very much endorse a dry academic processing of all this. This is a must for us not to also become broken robots murdering a civil rival. Any atheists or strongly secular reading this have to admit that the Christians who pray in sincere self-reflection and self-criticism, and seek ways to confront the mean world of man informed by Jesus the Son of God do have an edge on everyone else, because theirs is an old system that rises above the meanness and stupidity of man.
"Rises above the meanness and stupidity of man." That is part of our call to action. Fundamentally. Even if we mass arrest, and their are state sanctioned death penalties, the project is to rise above "the meanness and stupidity of man".
I must end with a personal statement. It will be embarrassing to my many good and truly smart atheist friends. I see this murderous faction as propelled by something spiritually evil. Their list of issues, and their uniform stances on each, it is just too dedicated to perversity, misery and death cult modes. This will have a harsh landing on atheist ears, but I see Satan or demonic entities in this story, and I see the Heavenly Father and Jesus the Son of God on the opposing side.