Senator Francis Case (R-S.D.) yesterday bitterly attacked Arthur M. Schlesinger, Jr. '39, associate professor of History, charging that the top Stevenson aide "had a long record of association with left-wing causes."

Schlesinger, in a telephone interview last night, called Case "an out-and-out liar." He went on to charge that Case was merely parroting a "mess of lies handed out to him by the Republican committee."

Criticizing what he called "the longtime stand" of the 35-year-old Schlesinger, Case said in a statement issued through the Republican National Committee:

"One would be naive indeed to think that he has changed his attitudes or will change them as director of research for candidate Stevenson or later, as adviser, if Stevenson were elected.

"Those who do not want Schlesinger as a presidential adviser in the White House had better not vote for Stevenson."

Case went on to cite a report of the House Committee on Un-American Activities. "Back in 1944, the House Committee on Un-American Activities, in an official report, devoted some space to Mr. Schlesinger. He was, the report stated, a member of the National Citizens Political Action Committee, 83 percent of whose members had records of affiliation with Communist or Communist front organizations."

"Never Member of NCPAC"

Schlesinger denied completely any association with the NCPAC. In a prepared statement, he declared: "I was never a member of any of these organizations, nor was I ever in any way associated with them. I have always been an outspoken anti-communist--a fact attested by the years of attack upon me in the Communist press. Senator Case's false statements are typical of the phase of desperation into which the Republican campaign is evidentially moving."

Republican National Committee aides last night attempted to clarify some of Case's charges. They disclosed that Case apparently was basing much of his facts on a report labeled "Appendix 9" dealing with a study of the NCPAC by the House Un-American Activities Committee.

Report Never Public

The aides said the report never was made public nor put to the full committee for a vote. The report, they continued, listed 141 members of the NCPAC of whom one was Schlesinger.

Neither the committee nor the attorney General ever listed NCPAC as subversive.

Case said the report listed Schlesinger as being connected with a number of other organizations, which he said were neither Communist-front groups or supporters of such groups.

Staff aides of the House Un-American Activities Committee late last night made available all public references of the committee regarding Schlesinger. These references cited among other things:

1. An articles Schlesinger wrote in the book review section of the New York Times December 11, 1949, in which he said: "I happen to believe that the Communist party should be granted freedom of political action and that Communists should be allowed to teach in universities so long as they do not disqualify themselves by intellectual distortions in the classroom."