It is the last week of March, 1988. Walter Cronkite has finally resisted all executive importunings that he renew his contract once more and announced that, Claude Pepper or no Claude Pepper, he will on Nov. 4 - his 72nd birthday - retire to spend his time disco dancing and sailing his boat, the boat Eric Sevareid once told him should be called "Special Assignment" because that is where he was when the announcer said he was on special assignment.

It does not promise to be as busy a summer as most. The quadrennial national political conventions have not been covered in full - "gavel-to-gavel" was the "23 Skidoo" of its time - since 1980, when NBC went ABC one better and summarized each evening in 90 minutes of edited tape, displacing Johnny Carson's guest host, and CBS played its summaries opposite "Disneyland" repeats. This year coverage will be limited to radio news-on-the-hour and a 15-second mention by Barbara Walters in the "Briefly" section of NBC Nightly News.

(Barbara returned to NBC in 1985. NBC rented Westminster Abbey for the requisite press conference. The most cogent questions were asked by the reigning Welsh monarch, Charles III, in on a press card from his undergraduate days, who wanted to know why American television had ignored the plebiscites which had declared England and Scotland republics. She answered that the American audience was tired of all this foreign news, but promised to take it up with NBC News executives when she got back to network headquarters in Houston.)

There is to be no television coverage of the Olympics this year. The Shah announced that because the Saudis would not let the price of oil go beyond $280 a barrel, he would insist on a $3 billion minimum for the rights to coverage in Teheran. In the event, the bidding went just beyond $4 billion and the winner was The New York Times, whose 'Us' magazine has just launched a video casette division. Since The Times's cash position was still short of the amount it bid, the newspaper itself was made part of the payment, leaving the corporation with only its book, magazine and broadcasting divisions. Negotiations had staled for a while over the Shah's insistence that The Times's slogan be included in the arrangement and the newspaper's refusal to comply. "There are certain things we just will not do," a Times executive explained.

But since that obstacle was cleared last Christmas, television executives have been contemplating a summer without live coverage. Despite the salubrious effect this is projected to have on the various botton lines, a certain malaise is manifest among network employes. Technical departments have been particularly anxious to try out some new equipment, and press agents have been enthusiastically coining words and phrases to describe it "so the average Joe can understand."

For several weeks now, the lassitude has been least at CBS. There are rumors that, on the very highest levels of the network, a plan is hatching, and some of the lower vice presidents whisper that they have heard from their secretaries who have heard from other secretaries that live equipment is being ordered in unusually large amounts - electronic cameras so small each can fit on a reporter's head like a beanie, thus letting him roam alone without his rabble of technicians; a mobile unit which can fit into a Volkswagen; tape machines which can be edited by thought waves; and the like. As usual, CBS is ordering its microwave dishes from Wedgewood.

The story, which has been rather closely held, will be announced next week. And it will be interesting to see how many will recognize it for the sad story it is. An exercise in nostalgia, really - a reaching for the vanished past, for glory days that by definition can never return.

CBS wants to resurrect the national nominating convention - the grinding routine of the primaries with different rules in every state, which reporters explain endlessly while waiting for returns worth reporting: the nominating speeches and the noisy floor demonstrations and the philosophic musings about how all this looks to foreigners; the backstage mancoverings and the Four Horsemen among the delegates on the apocalyptic convention floor, the anchor booths; the instant ratings; the convention managers feeding out celebrities to be interviewed; the candidates' wives . . .

With no foreseeable interest in the nomination of candidates for president, the intent was to find as analogous event which would engage the entire country - "something that really mattered to people." Sports was out, because it already occupies half the network schedule, most of it staged in specially designed television studios. Perhaps a really crucial movie role, like who would play John F. Kennedy in the forthcoming epic biography of Jim Garrison? That suggestion was rejected as too susceptible to planted plugs, a particular corporate sensitivity, but it set patterns of thought in motion, and there were several long, unstructured buzz sessions which were closed to all but a few highly placed participants, a buzz-session consultant, and secretaries bringing sandwiches.

What emerged, and what will be announced next week, is a national nominating convention for the successor to Walter Cronkite. Although there was no doubt that here at last was something of genuinely universal interest, the announcement has been held up this long until some difficult questions are answered and problems solved.

First, it has been difficult to get candidates of some general recognition to stand for the job. Bill Moyers was tempted but decided that he was too old; Peter Jennings, that he was too bald. Also, the real possibility had to be considered that ABC Sports would take over the form and discard the content, or that Dean Martin might use it to replace the Roast (the latter was dismissed as a concern when an NBC salesman was heard at the '21' bar to say that the Dean Martin Roast had 10 good years left in it).

But the big question was whether the public would expect Cronkite's chosen successor, whoever he (or perhaps she) might be, to be considered immovably safe in office for four years until another national nominating convention might be held, regardless of ratings. This question was not resolved, but the decision was made to go ahead because those present at the meeting are sure they will not be around in four years, so let those other fellows worry.