In this climate, some anarchists began to advocate and practice terrorism (i.e., attacks on civilians) or assassination, which they referred to as propaganda of the deed. United States President William McKinley, among others, was assassinated by an anarchist named Leon Czogolsz, who claimed to be a disciple of Emma Goldman. This was not a popular stance, and the tactic was condemned by others in the movement. Goldman, for example, disavowed any association with Czogolsz.
Depictions in the press and popular fiction (e.g. a malevolent bomb-throwing anarchist in Joseph Conrad's "The Secret Agent") helped create a lasting public impression that libertarian socialists are violent terrorists. This perception was enhanced by events such as the Haymarket Riot, where anarchists were blamed for throwing a bomb at police who came to break up a public meeting in Chicago. The writer J. R. R. Tolkien, in a letter to his son, breifly described anarchy as "philosophically understood, meaning abolition of control not whiskered men with bombs" (our emphasis).
The use of terrorism is still condemned by most libertarian socialists, but there remains no consensus on the legitimacy or utility of violence. The Tolstoian tradition of non-violent resistance is prevalent among some anarchists; others believe that violence (especially self-defense) is justified as a way to provoke social upheaval which could lead to a social revolution.
Errico Malatesta speaks for a large proportion of socialist anarchists when he says that it is "necessary to destroy with violence, since one cannot do otherwise, the violence which denies [the means of life and for development] to the workers" : many anarchists advocate violence insofar as they see it to be necessary in ridding the world of exploitation, and especially states.
Emma Goldman included in her definition of Anarchism the observation that all governments rest on violence, and this is one of the many reasons they should be opposed. Goldman herself didn't oppose tactics like assassination until she went to Russia, where she witnessed the violence of the Russian state and the Red Army. From then on she condemned the use of terrorism, especially by the state, and advocated violence only as a means of self-defense.