Non-violent tactics in attempts at integration in the South are useless unless backed up by a threat of possible of violence, John Lowry, a Freedom Rider who took part in integration picketing in Monroe, N.C., declared last night.

John Lowry, whose talk was sponsored by the Harvard Students for a Democratic Society, made the statement in defense of the policy of "meeting violence with violence advocated by the Monroe NAACP president, Robert F. Williams.

He emphasized, however, that the basic pattern of protest must be one of non-violence. Because of misunderstandings about the meaning of his statement, Lowry added, Williams has met with resistence from other integration leaders and has been suspended from his NAACP post.

Lowry said Williams made his original statement about the use of violence after sitting through a court session in Monroe at which a white man was charged with raping a Negro woman. Although corroborative evidence was submitted by a white woman, the man was acquitted.

On leaving the court, Lowry went on, Williams was asked what his impressions were. Williams replied, "We cannot expect justice from this court. We must meet violence with violence." Lowry's impression is that Williams was advocating only self-defense.

Misunderstandings of the statement affect Lowry directly because of his connection with Williams, although Williams had tried to dissociate himself from the Monroe picketing group.

Because Lowry is under indictment for kidnaping in Monroe, he needs the support of groups which Williams's statement offended. The kidnaping incident took place at the height of the racial tension engendered by the Monroe picketing.

According to Lowry, the charge stems from the fact that two Klu Klux Klan leaders, taken from their car by a group of Negroes, were forced to take refuge in Williams's house. Lowry said his only part in the incident was to move the Klansman's car to the curb.