cultures. Jihadi, mujahideen, and fedayeen are similar Arabic words that have entered the English lexicon. It is common for both parties in a conflict to describe each other as terrorists. On whether particular terrorist acts, such as killing non-combatants, can be justified as the lesser evil in a particular circumstance, philosophers have expressed different views: while, according to David Rodin, utilitarian philosophers can (in theory) conceive of cases in which the evil of terrorism is outweighed by the good that could not be achieved in a less morally costly way, in practice the "harmful effects of undermining the convention of non-combatant immunity is thought to outweigh the goods that may be achieved by particular acts of terrorism". Among the non-utilitarian philosophers, Michael Walzer argued that terrorism can be morally justified in only one specific case: when "a nation or community faces the extreme threat of complete destruction and the only way it can preserve itself is by intentionally targeting non-combatants,then it is morally entitled to do so". In his book Inside Terrorism Bruce Hoffman offered an explanation of why the term terrorism becomes distorted: The pejorative connotations of the word can be summed up in the aphorism, "One man's terrorist is another man's freedom fighter". This is exemplified when a group using irregular military methods is an ally of a state against a mutual enemy, but later falls out with the state and starts to use those methods against its former ally. During the Second World War, the Malayan People's Anti-Japanese Army were allied with the British, but during the Malayan Emergency, members of its successor organisation (the Malayan National Liberation Army) started campaigns against them, and were branded "terrorists" as a result. More recently, Ronald Reagan and others in the American administration frequently called the mujaheddin "freedom fighters" during the Soviet–Afghan War, however twenty years later, when a new generation of Afghan men (militant groups like the Taliban and allies) were fighting against what they perceive to be a regime installed by foreign powers, their attacks were labelled terrorism by George W. Bush. Groups accused of terrorism understandably prefer terms reflecting legitimate military or ideological action. Leading terrorism researcher Professor Martin Rudner, director of the Canadian Centre of Intelligence and Security Studies at Ottawa's Carleton University, defines "terrorist acts" as unlawful attacks for political or other ideological goals, and said: Some groups, when involved in a "liberation" struggle, have