What do you call the premeditated murder of 59 people by a heavily armed civilian? News media appear to have settled on the phrase ‘mass shooting’, avoiding the more incendiary term ‘terrorism’ because, we are told, there is no obvious motive behind the shooter’s actions. Masha Gessen in the New Yorkerurges us not to describe this as an act of terror because, so far, ‘no evidence has emerged that the Las Vegas shooter was motivated by political beliefs.’ Scott Shane in the New York Timesagreed that the ‘mass killing of innocents, even on the scale of Las Vegas, does not automatically meet the generally accepted definition of terrorism, which requires a political, ideological or religious motive.’

But there is no ‘generally accepted definition of terrorism’. There is an entire industry – populated by academics, government officials, judicial personnel, military experts, security consultants and international organisations – devoted to the pursuit of an agreed understanding, but a firm consensus remains elusive. Lord Carlile, the UK’s independent reviewer of terrorism legislation, reported in 2007 that ‘hard as I have striven, and as many definitions as I have read, I have failed to conclude that there is one I could regard as the paradigm.’ Walter Laqueur wrote in A History of Terrorism (1977) that ‘a comprehensive definition of terrorism … does not exist, nor will it be found in the foreseeable future.’

So we fall back on the definition proposed by the US government: ‘premeditated, politically motivated violence perpetrated against non-combatant targets by sub-national groups or clandestine agents usually intended to influence an audience’. This position – designed to exculpate the US state from any involvement in terror – also lends credibility to the idea that, without clear evidence of an ideological objective, the Las Vegas massacre wasn’t terrorism but a criminal act carried out by a ‘sick individual’, as Donald Trump described him.

Many people have rightly pointed to the double standards by which violence is interpreted and reported: when a person of colour carries out a murderous act targeted at civilians, it is more likely to be seen as a ‘politically motivated’ act of terror than the decontextualised, individualised violent actions of the typical white gunman. The trope of the ‘lone wolf’ versus the ‘politically motivated terrorist’ is heavily racialised.

A crime is often defined as terrorism rather than as ‘random’ violence if it has a clear ‘ideological’ dimension: these days, in the US and Europe, that usually means Islamism. It sometimes means white supremacism, but some of the most high-profile white supremacist attacks have been classified as ‘hate crimes’ and not terrorism. It’s worth noting that there have been many more recorded victims of white supremacist than Islamist violence in the US in recent years.

So we have the bizarre situation in which if there is no immediately identifiable ‘ideological agenda’, then there is apparently no terrorism. If there is a shout of ‘Allahu Akbar’ at the scene, then we are assured that the attack constitutes an act of terror; if not, then something else is going on.

But in what universe could the slaughter in Las Vegas be seen as somehow free of politics and ideology? Is there no ideology behind ‘white on white’ violence? Is there really no ideology underpinning the expression of frustration, rage, hatred or whatever state of mind is linked with mass shootings? Is ideology simply the preserve of other people, just as terrorism itself is so often seen as ‘what others do to us’? ‘Ideology,’ Terry Eagleton once wrote, ‘like halitosis, is … what the other person has.’

It is past time, whatever Trump may say, for a debate on gun control. But it may also be time to move away from understanding terrorism in terms of motives that are often obscure or unreliable. We might do better to understand terrorism in terms of the actions themselves: deliberate attacks on civilians that are designed to sow fear, which can be perpetrated by states and individuals, by national and sub-national groups, by people with any colour skin. Without a more systematic and consistent approach to understanding terrorism, specific groups and actions will continue to be singled out.

59 people were killed in Las Vegas and countless others terrorised by an act of violence that, while unthinkable in its horror, can’t be conceived simply as an unexplainable ‘act of pure evil’.