There is a widespread view that the terrorist threat in the West will, for the near future, consist mostly of ad-hoc attacks by individuals or very small cells. A recent article by the US writer Michael Hirsh, chief correspondent for National Journal, typifies this view. In the UK Matthew Goodwin has written that “the days when we faced a clearly identifiable threat with top-down chains of command look obsolete. Instead we have lone attackers or small cells of fanatics”.

In this post I question whether there has in fact been a trend towards self-starting small-scale plots and whether we should assume it will continue. The post specifically focuses on jihadism, as it poses the most serious current terrorist threat to the West (though far from the only one).

Has there been a trend towards self-starting small-scale plots and ‘lone wolves”?

Recent data does show a turn towards plots that involve very small numbers of attackers. A recent Bi-partisan Policy Center report which examined jihadist plots in the United States from 2011 to 2013 (inclusive) found that of 17 plots, 13 were carried out by individuals and the remaining four were by pairs.

A similar, but less dramatic, shift towards smaller cells is evident in Europe. Petter Nesser’s research found that from 2008 to 2012 (inclusive) there were 33 European jihadist plots, of which 11 were carried out by individuals, compared to four out of 72 for the period from 1995 to 2007. Then in 2013, two men with apparent jihadist motivations were charged over the murder of a British soldier in Woolwich, followed a week later by a possible copy-cat attack in France.

Not only are fewer attackers involved in jihadist plots in Europe and the United States, they are less likely to have received training or direct guidance from overseas jihadist organisations. This is particularly the case in the United States where none of the 2011-2013 plotters are known to have had such assistance.

This shows that there has indeed been a trend away from plots like the Madrid and London bombings towards self-starting plots by individuals and increasingly small cells. This has resulted in widespread commentary on ‘lone wolves’, including a report that senior police in Australia are concerned that “a ‘lone wolf’ strike will become the model of terrorist activity over the next decade.” Although many scholars push back against attempts to over-hype ‘lone wolves’, and the term is confusingly used in many different ways, the trend towards these self-starting and small-scale plots is clear.

What might have caused this trend?

Daveed Gartenstein-Ross notes that it is easy to misperceive temporary fluctuations in data on terrorist plots for massive, enduring shifts in the nature of the threat. Noticing a trend is one thing, judging whether it will continue requires looking at the broader context and the causal factors behind the trend.

Using Petter Nesser’s review of the literature on ‘lone wolves’, we can identify at least three key factors: organisational capability, strategic instruction, and tactical contagion.

The first factor refers to how the success of counter-terrorism measures against an extremist movement may leave it with little choice but to rely on self-starting attacks by sympathetic individuals. For example, effective crackdowns on violent white supremacist organisations in the United States from the 1980s resulted in a proportional increase in ‘lone wolf’ attacks by far-right extremists. Similarly, the United States has reduced the capability of al-Qaeda Central in Pakistan and al-Qaeda in the Arabian Peninsula (AQAP) in Yemen to direct or guide large-scale plots, partly prompting the shift in attack methods.

The second factor is that jihadist strategic texts and orations have increasingly promoted the ad-hoc approach. A book released by jihadist strategist Abu Musab al-Suri in late 2004 theorised an ‘individual terrorism jihad’ where the movement’s sympathisers attack at their own initiative wherever they can. At the time al-Qaeda’s leadership was reluctant to adopt this method, and al-Suri was soon captured. Since then, AQAP’s Inspire magazine adopted his ideas, explicitly promoted them, and provided detailed instructions in the English language. The highest ranking American in al-Qaeda, Adam Gadahn, also endorsed this approach in a video released in 2011 and a recent video by al-Qaeda’s leader Ayman al-Zawahiri called for “dispersed strikes” that can be carried out by “one brother, or a small number of brothers.”

The third factor is tactical contagion. Terrorists often emulate the tactics of other terrorists. Ever since the London bombings, ad-hoc jihadist attacks have proven more effective than sophisticated ones. The success (in terms of causing deaths) of the self-starting attacks in Fort Hood, Little Rock, Paris, Boston and Woolwich caused other aspiring jihadists to emulate them.

Will the trend inevitably continue?

These factors help explain the current trend in jihadist plots. But they do not provide reason to presume that trend will continue, because none of these three factors are static.

For example, al-Qaeda’s limited organisational capability to directly carry out attacks in the West may not be permanent. A recent American Enterprise Institute report, as well as the Bi-partisan Policy Center report, showed how al-Qaeda’s affiliates and associates have a far greater geographic presence and reach than they did a decade ago. With two al-Qaeda affiliates seizing territory in Syria, a series of jailbreaks throughout the Middle East and North Africa in July (including about 500 prisoners escaping in Iraq), and the Egyptian coup seemingly re-validating jihadism, al-Qaeda’s strength may be increasing. Consequently, it may well rebuild its external operations capability and return to launching direct attacks that overshadow the ‘lone wolf’ threat. Indeed, Thomas Hegghammer tentatively predicts a “second wave” of large-scale attacks in the West in four to six years’ time.

Similarly, al-Qaeda’s strategic instruction can change. The movement’s leaders and strategic thinkers may decide to instruct their followers to refrain from ad-hoc attacks. This could occur if such attacks continue to produce few casualties and little economic damage, or if al-Qaeda does manage to rebuild its external operations capability. A simple change of minds in key decision-makers could significantly reshape the threat.

Finally, because of tactical contagion a single successful attack of a different sort could also alter the current trend. If another plot like the London bombings (a cell of at least four people, some with training, and receiving direct guidance from al-Qaeda) kills over a hundred people, it could prompt emulation. Western jihadists may then once again form larger groups and make more effort to seek out external training and support. Recent UK arrests suggest that the Westgate massacre in Kenya, a large-scale urban warfare assault, has already sparked copycat attempts. An attack within a Western country would likely have a greater contagion effect.

What does this tell us?

This shows that the widespread view (that the predominant terrorist threat in the West for the near future will consist of ad-hoc attacks by individuals or very small cells) is less tenable than it appears. There has certainly been a recent trend towards these sorts of attacks, but the key factors behind the trend could well change, possibly quite rapidly. We shouldn’t assume that terrorist plots over the next decade will closely resemble those of the recent past.