MANY of the increasing – or perhaps just increasingly voluble – numbers of people in the West who self-describe as white nationalists talk of legitimate economic or social grievances. They shouldn’t kid themselves. They are part of a movement that, at its most violent fringes, is what it always has been: pure racist thuggery.

As their poisonous ideology infiltrates wider political discourse, so these extremists feel emboldened. In the UK, security services claim to have thwarted four far-right terrorist plots in the past year.

To combat racist white extremism, we must grasp its roots. As studies of violent white supremacists in the US show (see “ What makes a white nationalist? ”), these are often different roots to those assumed to underlie other forms of terrorism. Rather than devotion to the cause inspiring violence, pre-existing emotional trauma and a propensity to violence find expression in the cause.

That in no way excuses any crimes white supremacists may commit. But by helping us to understand society’s ugliest elements, such research can help society as a whole.

This article appeared in print under the headline “The roots of extremism”