In 1948, a 38-year-old North Carolinian and English professor at the University of Chicago coined a memorable phrase: “ideas have consequences.”

Richard Weaver, a traditionalist conservative from the Asheville area who briefly taught at North Carolina State University before landing his Chicago job, was making a philosophical point in his provocative book Ideas Have Consequences about the nature of truth and implications of denying its universality. But his famous phrase has been applied much more broadly — and immediately came to my mind when I saw the coverage of the Charlottesville protests.

The revolting white supremacist who drove his car into a counter-protesting crowd, killing one and critically injuring several more, produced only the latest in a series of killings and attempted killings motivated by political, ideological, or racial animus.

In May, for example, an Oregon bigot yelled epithets at two young women, one wearing a hijab, and then stabbed to death two of the three heroic men who stepped in to protect the women. In June, a left-wing extremist attempted to assassinate Republican congressmen and staffers at a Virginia park. Among the victims was the critically wounded Steve Scalise, majority whip in the U.S. House.

In these cases, and more I could list, personal problems, social isolation, and mental illness may have helped to precipitate the action. People who express differing opinions on issues are not necessarily morally responsible when others who share their opinions engage in violence. Indeed, the vast majority of people who hold even radical positions in politics do not become would-be killers or terrorists.

If you thought the federal government too often encroaches on the constitutional powers of states or the constitutional rights of individuals, that didn’t make you a co-conspirator with Timothy McVeigh in the Oklahoma City bombing. If you expressed concerns about environmental degradation, corporate power, and the adverse effects of industrialization and technology on human societies, that didn’t make you a co-conspirator with Ted Kaczynski in his Unabomber attacks.

None of which is to say that sharing certain ideas can’t make you partially responsible for whatever horrendous consequences might result. The easy examples are direct exhortations to violence. Almost as easy are examples of the ideologies of Karl Marx, Vladimir Lenin, and Adolph Hitler, all of which condone and require revolutionary violence.

Marx, scribbling his dangerous idiocies from the relative safety and security of 19th century London, may well be responsible for more human suffering and misery than any other single person in history. Yet he did not himself kill, torture, or enslave anyone.

The harder case to accept, but one that we must grapple with in the aftermath of recent events, is that when people in positions of power or influence abandon the norms of civil discourse and representative government, they aren’t just expressing a political opinion. They are implicitly endorsing a recourse to violence.

You see, politics is at its root a search for ways to accommodate strongly divergent points of view. If you don’t like a certain business, charity, church, or private group, you can just disassociate yourself from it. Governments are different. They produce coercive policies and collect coercive taxes. If your view of what government should do doesn’t prevail, the only way to disassociate yourself from it is to leave the locality, state, or nation in question.

Because people will never see their views prevail all the time, they have to be willing to live under policies they dislike if they want to continue living in their communities. But when their heads are pumped full of conspiracy theories, bigotries, and revolutionary ideologies, some come to believe that they shouldn’t have to either tolerate difference or exit — that there must be a third alternative.

This is a dangerous moment. I can see it in my hate mail. Over three decades of column writing, I’ve always received critical comments. But one recent, unhinged reader called me “the false prophet” and expressed the hope that someone will “silence my voice.”

There is an idea here. Its consequences are hideous.

John Hood is chairman of the John Locke Foundation and appears on the talk show “NC SPIN.” You can follow him @JohnHoodNC.