Tomorrow afternoon political satirist Mort Sahl takes to the Washington airwaves as a talk show host on WRC-AM. Sahl, 51, began his career as a humorist performing in nightclubs in the 1950s, his wry commentary placing him in the Dick Gregory-Lenny Bruce school of humor. He's been out of limelight during the past several years, working as a scriptwriter in Los Angeles and occasionally appearing at The Comedy Store nightclub there. His one-year contract with WRC is an attempt to return to radio and television. Sahl discussed politics and his new career during a meeting with Washington reporters and later during a private interview.

Q: How did you come to write jokes for John Kennedy when he was a presidential candidate?

SAHL: His father called me at the Essex House when I was appearing at Basin Street East. Joe Kennedy said he'd heard about me, that he wanted me to help his son. All I asked for in the form of patronage was the right to vote for who I wanted; I was not a Kennedy man. Then he was elected and all the people around him were telling me not to joke about him like I did about about other presidents. They wanted me to be reverent. Then they told me how much they loved him, and then when he got murdered and I said, 'Who murdered him?' the same people who told me they loved him told me to shut up.

Q: What kind of material did you write for him?

SAHL: Well, being a Catholic . . . At a Texas Baptist convention, they asked him if he was going to build a tunnel to Rome. He said, "I'm against public works projects in any form because they take away a man's pride." Or he'd say, "It's not the hereafter that's bothering me but the November elections." Stuff like that.

Q: What was your first reaction to a job offer from WRC?

SAHL: I rejected it out of hand. But the idea of new leadership at this network . . . See, the network is covered with cobwebs. But new leadership, the fact that they've got a personalized guy running it [Fred Silverman], means there's an opportunity with the network. I'm not interested in being on a local station! There's an opportunity on television, and I haven't had my hand in television in quite some time.

Q: Will you have a theme each show?

SAHL: I don't want to become what talk radio has become: monolithic axgrinding. I'm not into three hours of Ralph Nader proving that you can't cut diamonds in the back of a [sedan].

Q: Will you work with a tape delay?

SAHL: I think they'll have a seven-second delay so we have some control over profanity.

Q: Will you write new material every day?

SAHL: No, it'll come out of the situation. You know, it's hard to improve on what you give us in the papers. I read that Gov. Jerry Brown's father announced that if his son is reelected, he's going to marry Linda Ronstadt. That would mean that there's a real incentive for reelecting Gov. Brown because it'll force him to take a position on at least one issue before he leaves political life.

One thing I want to talk to the audience about is the American liberal. Now that he's running the country, I'd like to know how he explains the condition of it. I was on a television show in Chicago with Eric Sevareid and he kept saying to me - through his interpreter - America is well off because they caught Nixon. I was wondering why it's so wonderful now; it's almost comatose. Incidentally, we still haven't found out what the break-in of Watergate was all about . . . Oh, I know, it was Nixon's anxiety to read McGovern's speeches, an eagerness a lot of us didn't share.

This country is in a tremendous revolution. If you brought in "Gone With The Wind" now, it would have to be rewritten to please the National Organization of Women so that Rhett Butler is thrown downstairs by Scarlett. The ethics of the movie industry, which is largely made up of liberals, is, "I'm not a prisoner of the machismo culture my father was - I'm proud to say I'm ashame to be a man."

Q: Do you intend to invite guests on your shows?

SAHL: Occasionally, but not as a rule. You wind up plugging books on how to diet or how to be an urban terrorist.

Q: What are you going to do the first time Jody Powell calls you up and tells you the White House thinks something you said is unfair?

SAHL: You gotta do what you gotta do. I said to Jack Kennedy after the election, "You're the new sheriff, but I'm still a bank robber by vocation." And I meant it. People don't understand. I'm not on the left side; I'm not on the right side. I'm on the outside. And, man, that's where I'm best. I mean, who needs me otherwise?