IT IS APPROPRIATE that the first program in which presidential candidates may appear in prime time on television is to be broadcast tonight. It is also the night when the networks are supposed to launch their full schedules for the new season. As they watch the two candidates tonight, many will conclude that this is just a new nostalgic sitcom, "The Little White House in the Swamp."

There have been some desultory complaints in the newspapers that these candidates' appearances are not debates. But the newspapers go on calling them debates. It is as if print journalism has lost the heart to question and to resist tealevision. It connives in one more weakening of our vocabulary. It does much the same when it reports the televised news conferences of presidents as if they bore some relation to press conferences of the past. In both the "debates" and the "news conferences," reporters play the valet to power.

Let us stay with the question of language for a moment. For the preposterous situation in which America has placed itself over the trivial appearances of the presidential candidates in a televised encounter is the result of many influences.

What are not debates are described as debates; what are not press conferences are said to be press conferences. But that is not all. We speak of talk shows when they have nothing in them which resembles talk. We describe the paid performers who conduct them as hosts when they have none of the functions or qualities of hosts. Those who perform for them are just as falsely said to be guests.

Words such as "host" and "guest" are infinitely precious. They carry a great weight of treasured meaning. To break bread with someone has always in the past had something of the sacredness of an oath. Not the least of Macbeth's crimes was that he murdered Duncan while the king was guest in his house. To be a guest used to mean that one came unarmed to the table of one's host, and then slept unarmed and at ease under his roof. All our past literature, from the Old Testament and the Iliad on, is explicit about this relationship.

I do not see how it can be denied that much of its meaning has vanished from our lives. What obligation is there if one is invited to luncheon, and the bill is paid by the credit card of an employer? One is not a guest, one is an expense. The very casualness with which children come to their parents' table is an apprenticeship in incivility.

It is in fact not stretching the point too far to say that Iran's defiance of the obligations of a host country in its treatment of the members of a diplomatic mission is part of a much more general breakdown of manners, and this is perhaps all the more disturbing when one recalls how detailed and elaborate the Islamic culture has always been in laying down the rituals of host and guest in their mutual behavior.

When words weaken, our habits, our attitudes, our thinking, weaken with them. No one would worry about the silly appearances of the presidential candidates on television if they were not called debates. If we said that Ronald Reagan and John Anderson will perform tonight, dance tonight, sing tonight, we would give them the same due weight as we give "The Gong Show."

That is how they should be rated. If only Jimmy Carter was refusing to appear with them for the right reasons, what a blow for sense that would be. It was surprise and a delight to hear Sen. John Tower say that no incumbent president should take part in these follies. But he was merely worried about the unfortunate slips which any president may make. That is only a fraction of the point. No president should appear because no politician should appear.The journalists might belatedly set a standard by refusing to appear themselves.

An extraordinary mythology about the importance of the appearances has been erected on the flimsiest evidence. They have taken place only twice before -- in 1960 and 1976 -- and there is no solid proof that they mattered. The notion that they did matter rests on the dubious tracings of the opinion polls. But in as complex an area as the motives of the electors, the polls in fact create their own answers by forming the questions.

If they did not ask about the television appearances, they might hear very little about them from the voters, and nothing which made them seem in any way decisive. It has taken the head of a national association of the pollsters to say that, in their activity in an election campaign, the polls may not do more than supply jobs for a lot of people. They have become, he said with apparent distaste, a form of journalism.

But not only do we allow the polls to create the fiction that the television appearances are of consequence; they have this year supplied the criterion for determining who should take part in them. Here one reaches the level of the ridiculous. One gazes in almost mute stupefaction at the elevation of the League of Women Voters to a solemn role in the political process. Within four years it has been given an almost constitutional function, and scarcely a whimper has been raised against this travesty.

What possible justification is there for making it almost mandatory for a candidate to appear at their spinsterish invitation? I would make just as much and as little sense to give the task to the Lions Clubs. But the precedent is being set with no challenge other than that by the president. It would be no more bizarre and outrageous if, as a result of the interview which Jimmy Carter gave to Playboy in 1976, all candidates were now required to give such an interview. Why not build Playboy into the political process?

The League of Women Voters has no more qualification for deciding who are serious candidates than the Salvation Army. One could just as well entrust the decision to People magazine. Let it poll its readers in order to decide which candidates are serious. By judging the seriousness of a candidate by his ratings in the polls, the League of Women Voters in fact acknowledges that it has no valid crieteria of its own.

I now and then have a nightmare that all political decision in this country will in a matter of years be placed in the hands of Common Cause. The solemnity with which the pretensions of the League of Women Voters are now being taken is no less alarming. It represents an attitude which is creeping like a wasting disease into the body politic.It is a sick belief that there are organizations of worthy citizens who are more disinterested ans wiser than the rest of us and certainly than the actual politicans.

Common Cause and the League of Women Voters are in fact no more disinterested than any other semipolitical organizations. They represent the interests and attitudes of a small and influential section of the middle class. By and large, the professional middle class. One would not much mislead a visitor from Mars if one told him that the League of Women Voters represents the attitudes and interests of the wives of foreign service officers. I do not deny that they are worthy people; I simply question their political sense and acumen.

For even if they were as disinterested as is imagined, that would be itself disqualify them for the new role. Politics is far too serious to be left to the disinterested. It is a heads-down clash of interests. One knows that politics is being seriously practiced when politicians collide with each other like battering rams. Once they get prissy, like old maids, we should be alarmed.

In refusing to appear on tonight's political Gong Show, Jimmy Carter is making a straightforward political calculation. I happen to believe that he is probably right from his own point of view. I am certain that his challenge is right for the health of the political process. There is no reason why a politician should demean himself by responding to the invitation of a bunch of amateurs.Politics ought not to be amateur theater ads.

If his calculation is correct, he will have his reward. The effect of John Anderson appearing alone with Ronald Reagan may well be to make him seem an alternative to Republicans who are unhappy with Reagan. If it counts for anything, it is all in the dice. But this does not alter the fact that in pursuit of his calculated self-interest one major candidate has seriously brought into question one of the most fatuous developments in the recent history of American politics.