By Harry F. Rosenthal Associated Press Writer , N.M. When the audience is right and the mood is right and when a lifetime in politics tells him it’s time to aim for the gut, then and only then does he invoke the memory. He never says assassination. Or killing. Or death. “I spent 14 years of my life in close association with him,” he says. “I was with him in Massachusetts and I was with him in Dallas. And I was with his brother in Massachusetts and I was with him in Los Angeles.” No names; there is no need. The audiences know. The iden tification is made. The speaker is Lawrence F. O’Brien, the man who put John F. Kennedy into the White House, who tried to put Robert F. Kennedy there too. Now, as national chairman of the Democratic Party, O’Brien is on the road selling unity and hope for his tattered and pauperized troops. Mostly he sticks to praising Democrats and damning Republicans. But for certain audiences — the ones he remembers from the heady days of the 1960 campaign — he makes the Kennedy connec tion. It usually comes near the end of the speech, when he’s done with talking about unemploy ment or inflation or what he calls the unresponsiveness of the Nixon administration. “Throughout this nation today” the litany begins in a voice barely audible, “we hear a great deal about extremism, permissiveness.” He pauses and looks down at the lectern as if somehow the words will be there. “We know extremism and we know violence. I spent 14 years. “What I resent more than anything else,” O’Brien says privately, “are these attempts to suggest that the Republicans are for law and order and that we think extremism is good. That’s why I bring up the Ken nedys. My God, after Dallas, after Memphis, after Los Angeles, how could we?” There is an almost mystical belief among Democratic pro fessionals in O’Brien’s abilities as a political Merlin. When they went looking for a national chairman earlier this year, the man they first turned to was the 53-year-old O’Brien — the architect of John Kennedy’s Senate and presidential vic tories, the manager of Robert Kennedy’s and then Hubert Humphrey’s campaigns in 1968 and the Democratic chairman in the latter stages of that cam paign. When summoned back to the chairmanship, O’Brien had been in private life only a short time, had undergone a disastrous businessee, had only recently started public relations firm of his pty and was committed to do a ma jor book. “TI could not —and I knew it go back as chairman of the national party and _ confine myself exclusively to basic organization,” says the man John Kennedy called “the best election man in the business. ‘I felt compelled to speak out, ex press my views. . .to present, if I could, some leadership to the party.” And speak out he does. On a 5- day swing to California, Arizona and New Mexico, O’Brien held seven news conferences, made eight speeches, granted 11 television and radio interviews —some lasting an hour — and had more than a half dozen private meetings with politi cians. That particular trip, typical of the ones that will take him to 34 states before the Nov. 3 election, began in New York early on a Tuesday before the streets became clogged with cars. O’Brien’s chauffeur provided by a friend — first picked three Washington staff alis Hi at their hotel and then stopped at the U.N. Plaza apartments to get the man the staff calls “The Chairman.” Even at that hour, O’Brien — always the politician —stops to shake hands with the doorman, to chat with a policeman and two passersby. As soon as O’Brien has settled in his seat on the 747 to Los Angeles, his secretary — a pert 24-year-old named Julie Schlessinger — hands him a black looseleaf binder with a rundown on the candidates he’ll meet in California. It lists, suc cintly, their issues, their strengths and weaknesses. O’Brien studies it more than an hour, then starts to talk about the problems of the Democratic Party. Political talk plainly is O’Brien’s chief relaxation. There is no need to ask about his famed memory for name and dates. When the plane is over Indiana he remembers what that delegation did in the 1960 convention. Over Missouri he talks of having been in Harry Truman’s home and who else was there. In Los Angeles, he is met by Frank Cullen, once an aide to former Gov. Pat Brown, who gives O’Brien the kind of bare bones briefing he likes. Waiting for him at an airport hotel is John chief consultant to the Democratic caucus of the state assembly. Again a briefing: “In this district we got 68 per cent registration, I don’t think we'll lose...that one looks bad. ..That guy was voted the worst legislator by the press corps.” O’Brien and John V. Tunney, the Senate candidate, are the only main speakers that night at a $125-a-plate fund raising dinner. O’Brien, his Countess Mara ties and shirts now re placed by a tuexdo and black tie, sits at the head table next to movie star Angie Dickinson. He looks bored. After the long entertainment it’s finally his turn to speak. He talks only eight minutes. This speech has no outside the hall, O’Brien mutters: “They ought to decide whether to have a political evening or a concert.” Tunney had asked to talk with O’Brien in his room. At 12:30 a.m. Tunney comes in and they talk for 1% hours in the bed room, O’Brien in pajamas, Tunney in black tie. When O’Brien finally turns out the light he has been up for more than 24 hours. Democratic Chairman Lawrence O’Brien, confers with California gubernatorial candidate Jess Unruh