AS GOOD BETS go, one of the better ones must be that during the entire national drama we call the 1980 presidential campaign at least three unique American characters will fail once again to make so much as a cameo appearance. The three absentees -- missing for longer than Judge Crater -- are the Deserving Welfare Mother, the Competent Bureaucrat and . . . the Happy Farmer.

No reporters were present the last time any positive words were spoken by any presidential nominee (or even by his hand-picked running mate) about the Deserving Welfare Mother and/or the Competent Bureaucrat. Something more than blind faith tells us that such folks do exist and show up each day where they are supposed to. Of course, all of us can recite from memory the whole syllabus of crimes perpetrated by their opposite numbers: the bumbling bureaucrat and the thieving welfare recipient. We could regale that same anyone with tales of how some giant federal program was buying Betamaxes for the aborigines or how one welfare mother (always outside this immediate area code and zip code) has two Mercedes, a Coupe de Ville and more sable coats than the national ticket's whole family. Surely everyone one not in a semi-comatose state has already heard most of the these tales from the Twilight Zone.

But invincible faith aside the question of the Happy Farmer is a more serious one. Most of us know, or have been told by someone we trust, about the goverment worker who works well in the public interest and who actually came up with an idea that savd time, money and trouble for other citizens. The same holds for the gallant welfare mother who provided her children with tons of love, direction and inspiration and one of whose sons made Honorable Mention All-American and won a Rhodes to Oxford because of his mother's example and encouragment and so forth.

But no once -- no one -- has reported the sighting of a Happy Farmer anywhere at any time. This is a litle upsetting to some of the rest of us who have not been told for two centuries (as farmers have) that we are the "salt of the earth." The majority of the rest of us are delighted if our views and interests are given even a brief, respectful hearing by Congress. But not the farmer. He both expects and receives from Congress and the White House respect that frequently gives to reverence.

The farmer's doughty independence is boringly (for the non-farmer) sung to in spite of the fact that each succeeding secretary of agriculture spends more than half his time in office trying frantically to come up with new subsides, loan guarantees, special insurance plans and irrigation and power schemes to help the farmer at the expense of the non-idependent non-farmer such as the welfar mother and the bad old bureaucrat. The remainder of every agriculture secretary's term is spent unsuccessfully fighting off farmers' demands for his scalp. Farmers may be praised and even emulated (the Rural Connection is currently being emphasized by both the president and his Republican challenger), but the farmer is not happy.

Why don't we all post a eward for the first verifiable sighting during the 1980 campaign of any of the Big Three? (Relatives not eligible).