Left-wing terrorism or far-left terrorism is terrorism motivated by left-wing or far-left ideologies, committed with the aim of overthrowing current capitalist systems and replacing them with communist or socialist societies. Left-wing terrorism can also occur within already socialist states as criminal action against the current ruling government. The majority of left-wing terrorist groups originated in the aftermath of World War II and were predominantly active during the Cold War. Most left-wing terrorist groups that had operated in the 1970s and 1980s disappeared by the mid-1990s. One exception was the Greek Revolutionary Organization 17 November (17N), which lasted until 2002. Since then, left-wing terrorism has been relatively minor in the Western world in comparison with other forms of terrorism, and is now mostly carried out by insurgent groups in the developing world. Ideology Left-wing terrorist groups and individuals have been influenced by various communist and socialist currents, including Marxism. Narodnaya Volya, a 19th-century revolutionary socialist political organization and left-wing terrorist group operating in the Russian Empire that killed Tsar Alexander II of Russia in 1881 and developed the concept of "propaganda of the deed", is considered a major influence. According to Sarah Brockhoff, Tim Krieger, and Daniel Meierrieks, while left-wing terrorism is ideologically motivated, nationalist-separatist terrorism is ethnically motivated. They argue that the revolutionary goal of left-wing terrorism is non-negotiable whereas nationalist terrorists are willing to make concessions. They suggest that rigidity of the demands of left-wing terrorists may explain their lack of support relative to nationalist groups. Nevertheless, many on the revolutionary left have shown solidarity for national liberation groups employing terrorism, such as Irish nationalists, the Palestine Liberation Organization, and the South American Tupamaros, seeing them as engaged in a global struggle against capitalism. Since the nationalist sentiment is fueled by socio-economic conditions, some separatist movements, including the Basque ETA, the Provisional Irish Republican Army, and the Irish National Liberation Army, incorporated communist and socialist ideologies into their policies. David Brannan writes that left-wing terrorists and insurgents tend not to engage in indiscriminate attacks on the public as it not only runs contrary to the socialist ideals they espouse of being protectors of the working class, but they also do not want to alienate large swaths of the working population as such organizations and individuals seek to gain their support. Other researchers argue that left-wing terrorism may not be less indiscriminate than its right-wing counterpart. History Left-wing terrorism has