It is a cold and dark January night in the Swedish town of Eskilstuna. Fredrik Nyqvist and a friend are walking home from the founding meeting of the local section of the minuscule Libertarian Party.

Suddenly, four men in black clothes and facemasks show up, knocking the two unconscious. One of the offenders later bragged about jumping on Fredrik's head, causing injuries that kept him hospitalized for days.

The two libertarians had no way of identifying the perpetrators and assumed it was just a regular criminal incident. They could not know they had just become victims of political terrorism. But they would soon find out.

At his home a couple of days later, a third party member received a note from a group claiming responsibility for the attack, and was warned:

We hereby give you a chance to terminate all political activities. Failing to do so, you may be the next one to be physically reminded of the consequences of pursuing anti-working class policies.

The Antifa, or anti-fascist, movement of Charlottesville, Portland, and Berkeley fame did not come out of nowhere. It is a carbon copy in name, tactics and ideology of groups that have been active in Europe for decades. The website of the Swedish organization is www.antifa.se.

Originally an anti-Nazi body in a pre-WWII Germany, organizations resurfaced in various European countries in the 1980s and 1990s, attracting plenty of attention during the anti-globalization protests at the turn of the millennium. Since then, Antifa have systematically used violence as a political tool. Victims are in no way limited to Nazis or the alt-right. Mainstream center-right politicians, leftist mayors and government bureaucrats have been targeted. Apart from the usual assaults, Antifa members have made arson and gas attacks.

An original Antifa specialty is rioting, making up the Black Bloc of more mainstream leftist demonstrations, not least in protests against summits of international organizations such as the International Monetary Fund and the World Trade Organization. The most recent example was the G20 meeting in July, when large parts of Hamburg, Germany were under siege and private property worth millions of dollars was vandalized. "Welcome to hell" was the message.

The American outfit copycats its elder siblings from across the pond, blending in with democratic leftist groups (acting as self-appointed bodyguards), creating Lenin-style united-front coalitions to gain legitimacy (who is not an anti-fascist?) and applying a very wide definition of the term fascist (most people they don't agree with).

The extreme-left tradition of misusing terms to their own benefit is not only an Orwellian cliché, but also an historic reality. Remember that the official East German name for the Berlin Wall was "Antifaschistischer Schutzwall" or Anti-Fascist Protection Rampart.

In The Washington Post, Dartmouth historian Mark Bray, author of the recent book Antifa: The Anti-Fascist Handbook, whitewashes the movement, putting forward the argument that Nazis need to be dealt with at an early-stage. But neither libertarians nor Social Democrats are Nazis. Do the ends really justify the means, especially when the end is undemocratic socialism?

In Germany, with its particular history, freedom of speech is more restricted than in the US. Nazism and its symbols are forbidden. And recently, after the Hamburg riots, authorities closed down a website used to coordinate the extreme-left activities. It is in this context that Americans should remind themselves that the First Amendment also protects authoritarian right-wingers and white supremacists.

Just as its European counterparts, the US Antifa is a mix of mainly left-anarchists and hard-core Marxists. Not trusting the government to protect them from authoritarian right-wing rule, they rely on pre-emptive "self-defense." The more experienced Europeans, working in loose networks and strategically appearing under different group names, opportunistically set up and dissolve bodies as they go along. The same people commit one crime under one banner, going with another headline for the next deed.

One particular difference is that some European Antifas have close ties to certain labor unions, anarcho-syndicalism being a weak tradition in the US. This is one of the reasons why the struggle against capitalism is considered just as important as the fight against fascism. In fact, the latter is viewed as an integral part of the former.

Which brings us to the paradoxical enmity between European Antifa and libertarians, something that to my knowledge has not yet revealed itself in the US. In many ways, anarcho-syndicalism/left-anarchism is a cousin of libertarianism, or at least of anarcho-capitalism. After all, the US Anarcho-Syndicalist Review used to be called the Libertarian Labor Review.

So, should libertarians not be favorably inclined towards a movement that fights authoritarianism and centralization, standing up against the ugly collectivist ideology of racism? Well, it takes two to tango. And Antifa itself does not seem to think we have much in common.

Our beliefs in the rule of law, property rights, and markets are anathema to them. So, on the contrary, they are not allies, but rather a major challenge to the liberty that we cherish. Libertarians do not subscribe to threats, physical violence, and vandalism as political methods. The non-aggression principle, remember?

Somewhat ironically, European Antifa activists tend to belong to the intellectual middle class, later going on to careers in the media and academia. This is one of the reasons why they are handled with kid gloves by parts of the establishment here. Important parts of the chattering classes identify with or are apologetic of the group, a tendency that also seems to be copied in America.

True, the very top of the establishment in the US is more inclined to make excuses for the other kind of extremism. So the American problems might not be the same as the European. But beware.

Due to its political sophistication, the Swedish security police reckon that the autonomous leftist groups, of which Antifa is the most important one, constitute a more serious threat to the functioning of the country's democracy than do the two other forces being watched, namely radical Islamists and neo-Nazis.

The false equivalence is less false in Europe. And may become so in the US as well.