WASHINGTON (UPI) — The White House said today that ‘not once does it appear’’ in transcripts of Watergate con versations that President Nixon was engaged in a criminal plot to obstruct justice. In issuing a 50-page summary “white paper,’’ the White House launched a full-fledged attack on John W. Dean III, fired one year ago today as presidential counsel. Much of the document dealt with Nixon's Sept. 15, 1972, and March 21, 1973, conversations with Dean, who later became the President's chief accuser. The summary was presented to substantiate Nixon’s asser tion Monday night that his release of 1,200 pages of the transcripts would clear him of any involvement in Watergate and would ‘‘tell it all.” In reference to the Sept. 15 conversation, the day the original seven Watergate indict ments were handed down, the summary says that Nixon told Dean: “But the way you have handled all this seems to me has been very skillful, putting your finger in the leaks that have sprung here and have sprung there.”’ The white paper said Nixon made the statement “in the context not of a criminal plot to obstruct justice as Dean al leges, but rather in the context of the politics of the matter.”’ Dean testified at the Senate Watergate hearings last sum mer Nixon in that conversation had congratulated him for containing the investigation of the Watergate break-in. In reference to Nixon's conversation with Dean on March 21—the date the Presi dent said he first learned of the scope of the cover-up—the white paper said the President asked Dean: ‘‘Tell me this: Did Mitchell go along? ‘Did Colson (former White House special counsel Charles W. Colson) know what they Watergate conspirators G. Gordon Liddy and Fr. Howard Hunt) were talking about?” “Did he (Colson) talk with Haldeman? ‘Did he (Haldeman) know where it (the information) was coming from?” The summary did not say how Dean answered the ques tions, which it said were among more than 150 Nixon asked of Dean at the meeting. In the conclusion of the summary, the White House said: ‘‘Throughout the period of the Watergate affair the raw material of these recorded confidential conversations esta blishes that the President had no prior knowledge of the Watergate break-in and that he had no knowledge of any cover up prior to 1973.” “In all of the thousands of words spoken, even if they are not clear and ambiguous, not once does it appear that the President of the United States was involved in a criminal plot . Continued on Page 11)