Undoubtedly emboldened by the election of Donald Trump, a resurgent white nationalist movement marched last Friday (11 August), waving swastika flags and chanting "white lives matter" and "blood and soil" (a familiar Nazi trope) in the Virginia town of Charlottesville.

Thirty-five people were subsequently injured and, tragically, a 32-year-old woman, Heather Heyer, died after a car driven by a suspected neo-Nazi rammed into anti-fascist protesters.

Events in Charlottesville have sharply divided opinion. Not in terms of the march itself – it seems fair to assume that most Americans are not sympathetic to neo-Nazis (though Donald Trump has equivocated) – but in terms of the political response to it. The resultant online vitriol has neatly slotted people into one of either two camps: those who wish to meet fascists at protests such as this one with violence, and those who believe that fascists should be allowed to freely organise much like any other group.

It would be useful to draw some of these arguments out and examine them briefly, at least to the extent this is possible within a short article.

To start with, I am not squeamish about confronting fascists with physical force. I once found myself on a train in Britain with a loud, belligerent Holocaust denier. 'On a train with' doesn't quite do the confrontation justice: he was in my face, shoving his theories about Jewish control of Isis and the 'gas chamber hoax' down my throat from the seat directly opposite. I ultimately used the threat of violence to eject him from the carriage and would probably do so again in a similar situation.

I would therefore stand on flimsy ground if I started to wax incandescently about others using force against organised fascists, especially if, rather than being made to feel uncomfortable on a train, their relatives were sent by train to be murdered by that person's ideological antecedents.

There are, however, a few things which I think are worth keeping in mind when deciding to confront fascists with – let's be clear – fascist methods.

The first is that the problem with any definition of fascism – and increasingly any definition of violence – is that it is as slippery as a wet bar of soap. To give an example: I spent much of last week arguing with more than a few leftists who were busy denouncing the entire opposition to the authoritarian government of Venezuelan President Nicolas Maduro as 'fascist'. Considering around 80% of the population of Venezuela opposes President Maduro, the term has evidently lost all meaning, and functions mainly as a means to delegitimise one's enemies. Anyone with a passing interest in the Spanish civil war will be aware of the Trotskyists and anarchists who were falsely labelled as 'fascists' by supporters of Stalin and as a consequence jailed and murdered.

The same problem occurs as soon as you accept the notion of 'harmful' speech (beyond direct incitement to violence, which is fairly easy to compartmentalise). The respected psychologist Lisa Feldman Barrett recently published an essay in The New York Times titled When is speech violence?". In the piece she made the startling claim (syllogism actually) that "If words can cause stress, and if prolonged stress can cause physical harm, then it seems that speech - at least certain types of speech - can be a form of violence." This is a recipe for mass censorship deployed on the basis of an entirely subjective emotional response called 'stress'.

The point is that, just as I am unable to think of anyone I trust enough to decide which books I can read, I cannot think of anyone I would give carte blanche to decide who is or is not a fascist – i.e. to grant permission to beat a person to a bloody pulp (or kill them perhaps – why stop at punching?)

I don't accept the liberal and conservative position by any means, which is to put your faith in the power of the state and accept tout court that it should have a monopoly on violence. This prompts a fresh set of objections (or perhaps qualifications). The first is that the United States federal government has historically (and not only historically) been extremely poor at protecting African Americans from violence. It has even at times acquiesced in the infliction of it.

And so the status quo admonition to black Americans to throw their lot in with law enforcement is a bit like instructing someone with their head in the mouth of a lion to close their eyes and not look at the teeth. Those without power must to some extent make their own rules or perish. This is what the distinction between 'punching up' and 'punching down' gets at.

Yet Nietzsche's famous warning that whoever fights monsters risks becoming a monster himself is worth bearing in mind. You cannot behave abominably when you lack power and expect to undergo a metamorphosis when you have the weapon in your own hand. This is the lesson of every failed revolution: not that revolutions must inevitably fail, but that human beings do not moderate their behaviour once they have power. Instead they become a more deplorable version of themselves, however lofty their ideals were to begin with.

Perhaps I am using the wrong form to say that I remain unsure as to where I stand exactly on the freedom to confront fascists with physical violence. Sureness is after all the central pillar of the column-based polemic, which the Collins English Dictionary defines as a "very strong written or spoken attack on, or defence of, a particular belief or opinion".

Not that there is a shortage of this stuff about. If social media has altered political discourse in the west it has done so by handing a megaphone to the most vitriolic representatives of every political community. One hallmark of the deluge of 'takes' we are subjected to nowadays is the rise to prominence of the pundit with an opinion on everything. These cerebral eruptions are often ill-informed yet advanced, paradoxically, with absolute certainty.

Instead this sums up precisely the type of person I don't want to listen to on a subject as potentially consequential as this one: people who exhibit not a shred of doubt that they are in the right. They are to be distrusted anyway, but especially so in times as volatile as these.