extremism
Definition
Extremism refers to the adoption of radical beliefs or worldviews that serve to motivate or justify violence, and contemporary forms increasingly resist classification under a single, coherent ideological label. Perpetrators may mix seemingly contradictory ideologies, hop between distinct belief systems, or draw on conspiratorial content without meaningful affinity to any one tradition. The diminishing influence of hierarchical extremist organizations, the rapid expansion of online ecosystems, and the central role of conspiracy in sustaining violent commitment have all contributed to this fragmentation. Young people are disproportionately represented among those radicalized under these conditions, with U.S. START data recording a 311% increase over the past decade in youth radicalized without formal ties to designated extremist organizations. At the same time, evidence from programs such as Toronto's ETA suggests that rising case counts may partly reflect shifts in practitioner classification rather than a genuine surge in ideologically mixed offenders.
Sources: Horgan & Shayler (2026)
Applications
Extremism and Ideology
The relationship between extremism and ideology is less straightforward than traditional classification frameworks assume. Some offenders select ideological content casually to legitimize violence or seek notoriety, displaying low commitment to the substance of any given belief system, while others engage in more deliberate mixing or sequential hopping between distinct ideological positions. Distinguishing these processes matters for both research and practitioner response, yet terminological inconsistency across agencies and disciplines has impeded that effort.
Sources: Horgan & Shayler (2026)
Extremism and Conspiracy Theories
Conspiracy belief occupies a central place in driving and sustaining many contemporary forms of violent extremism, functioning as connective tissue across otherwise disparate ideological content. This role has grown alongside the expansion of online ecosystems in which conspiratorial narratives circulate rapidly and reinforce radicalization outside any formal organizational structure.
Sources: Horgan & Shayler (2026)
Extremism and Radicalization
Radicalization increasingly occurs without formal ties to designated extremist organizations, a pattern especially pronounced among young people. The processes involved, whether ideological mixing, hopping, or the absorption of conspiratorial grievances, demand greater conceptual precision than current terminology provides, and empirical evidence on these pathways remains limited.
Sources: Horgan & Shayler (2026)
