PRESIDENTS OF the United States of Television, which is where we live now, should know that the one thing they must resolutely avoid becoming is not ineffectual or controversial or even an unindicted co-conspirator. The thing they must avoid becoming a BIG DRAG.

Television has the capacity to turn humans into big drags faster than any other medium ever could. No matter how hard People magazine tries to compete, TV is still king of the dragmakers. President Carter should know this. President Carter's advisers, some of them McLuhan-cool media gurus, should certainly know this. But the fact is, President Carter is a big drag on television; and if he were not such a big drag on television, he probably wouldn't be hearing such a chorus of criticism now about the wishy-washyness of his administration.

Carter was caught live on the ABC Evening News last week just after the passage of the Panama Canal Treaty. We saw him approach the podium and the microphones and his pipeline to the nation and just before he turned on his merry mortician's smile, he made what looked like a sigh, perhaps even a groan, as if to say," I'm not looking forward to this any more than you are."

It's a big lie that TV cameras always tell the truth or that they reveal the hidden souls of every mortal who steps in front of them. Phonies, frauds and fakes can thrive on television as well as anyplace else. But one thing that almost always does come across on the air is whether or not a person is glad to be on television. Jimmy Carter does not seem glad to be on television; and when he appears, sometimes looking as if 14 different people had adjusted and re-adjusted his tie, viewers may feel like they're a blind date being forced on someone by a meddling mother.

Richard Nixon was never a big drag on television. Big Drag! Ho, was ever there drag less? He was ferociously entertaining to the last (and, if one charitably overlooks the hokeyness of the Frost-Nixon shows, even after the last); from the Checkers speech to the final bye-byes, Nixon was a TV spectacular. Gerald Ford seemed an irretrievably dull man, but at least on television he was able to recapture some of the titillating suspense that Harold Lloyd evoked dangling from the hands of a giant clock. Ford's television presidency was like an "Airport" movie; disaster always just a few clunky scenes away.

Of course politicians don't have to be on television to be big drags. Have you ever met one? And television doesn't perform its dragifying function only on politicos. Performers who might have had long and lucrative careers of fooling the public in other eras can be made drags overnight by television exposure. This doesn't mean TV ends those careers; the demand for personalities on television is so enormous that a large number of drags are bound to survive, even prosper.

A line should be drawn somewhere.

Some realy big drags on television reached that status through overexposure. John Ritter seemed a fairly funny young comic actor when he began starring on "Three's Company" - but he became a crowd; it is now hard to find a variety special on which he is not a guest star. Debby Boone might be a harmless little crashing bore if she weren't so omnipresent; one more "You Light Up My Life" and we'll all be yearning for darkness. Mere mediocrities like Barry Manilow, John Davidson and David Brenner become Big Drags through relentless, even vicious, television exposure.

You just hear their names and your spirit sinks.

Sometimes a tiny appearance on television can invoke Big Dragdom instantly; witness Vanessa Redgrave at the Academy Awards. She went from heavenly left-wing crypto-suffragette into insufferable idiot-nuisance right before our very wary eyes. And then when it became apparent that her fit of pique was in fact to be the highlight of the program, the Academy Awards became a big drag as well, more so perhaps than in any previous year.

Woody Allen, on the other hand, has become a very big drag by not appearing on television, and by making such a point of not appearing on television (except for a short interview with the fitfully draggy Dick Cavett). People are free not to appear on television - though there is no telling how long this state of mercy will last - but when they run around acting like this perverse form of celibacy is somehow a virtuous mission, they become among the biggest drags of all.

Some big drags reach that status only while on TV; in other media they regain their pre-TV decency. Thus does Gore Vidal get to be quite a pain hopping from talk show to talk show every time a new book of his comes out, and all the while carping on the air about how terrible TV is, but resuming life as an apparently civilized creature when not on the air. Of late he's even stolen Fred Allen's old line about TV being "moving wallpaper" and says it every time he sees a little red light. He thinks he's beating the system. He's not. A minor irritant as an actor, David Hartman graduated into the ranks of the neutron drags when he took over ABC's "Good Morning, America" show, where his over-extendedness recently extended to a harangue about how young actress Brooke Shields was being exploited. This was mere instants after Hartman himself had interviewed her - and thus helped plug her allegedly exploitative movie, "Pretty Baby" - on the show. Jimmie Walker burst onto the little screen as a rambunctions young talent (introduced by Jack Paar on his short-lived ABC late-night show) but has become an increasingly unwelcome "J. J." on the rapidly wearying "Good Times."

Hal Linden ("Barney Miller") and Dick Van Pattern ("Eight Is Enough") lead the legions of those big drag small time TV actors who try to convince you that watching them is a cleansing experience and that their hackneyed, hickheaded sitcoms are somehow in the vanguard of a cultural renaissance.

Sorting out the big from the little drags in the TV sports world is a precarious act, but surely there has to be a corner in Mudville reserved for the likes of Curt Gowdy, Jim McKay and especially for Mr. Squints, Joe Garagiola, one of the few people to make a career in the show business out of the fact that he was failure in baseball. Up to a point one may think, "More power to" such dunderheads, but then simple sanity sets in and you realize what you are endorsing.

Talk show hosts like Merv and Mike and Phil may be insipid and annoying, but they tend to know their places and stay in them. It's when TV personalities try to expand their spheres of influence that they can turn truly unbearable. The classic case in point is Steve Allen, who provided us with laugh upon laugh through year upon year and always seemed happy with his role. That he insisted on writing songs the way accountants write checks - and singing them the way an accountant would probably sing them - was at worst a tolerable vice.

But then why, oh why, did the man once affectionately known as Steverino have to besmirch his good name as a zany with "Meeting of the Minds," a ludicrous televised coffee klatsch with Great Thoughts where the paper napkins should be? In the long hard history of fatuous pseudo-intellectual presumptuousness, nothing quite matches Steverino sitting down with the Marquis de Sade, Frederick Douglass, the Dowager Empress of China and Jayne Meadows to discuss the fate of mankind. It isn't quite horrible enough to be hideously funny but it can sure take a prominent place among the greater drags in all of television, even public television, where even the dregs of drags can find a home.

There are so many others - Wolfmand Jack, Bill Cosby, Cher, Orson Bean, Robert Blake and Robert Conrad - and they comprise such a vast, marauding army that occasionally one must just turn off the set and seek a less abrasive form of boredom. Many of the big drags on television are of course, cameless and, obviously, big drags on purpose. One can forgive the man selling the space age storm windows because, well, what else is he to do - play Hamlet on Broadway? Sing Pagliacci at the Met? Write about television for a newspaper? On the other hand, one can be too forgiving. Surely Tom Brokaw would be just as happy as an insurance amn in Dubuque, and we would all be spared a big drag, and a big drag in the morning at that.

What the president of the United States has to do is get himself out of these rank - away from the Captain, Tenille, Henry Winkler, Barbara Howar, Helen Reddy, Mac Davis, Anson Williams, and all the others whose appearances on television are so numerous or so numbing as to be self-destructive. Wending his way through the channels recently, constant viewer came upon a woman with a voice like raspberry sherbet struggling with the private parts of a naked and dead turkey. She was saying, "The French usually whack these off." JULIA CHILD - WHAT A DRAAAG!

If television is communicating Jimmy Carter as he really is, Jimmy Carter should change because the viewership is the electorate and, more than that, has a right to expect entertainment from a president. In this respect, Nixon rarely let us down - the way Pinky Lee, Kathryn Kuhlman, Joe Pyne, Rocky the Flying Squirrel, Dunninger, Soupy Sales, Ed Sullivan, "The Millionaire" and "You Asked for It" rarely used to let us down - and one longs to witness some of his classic TV gigs again. If only Nixon had put videotape instead of audio tape in the Oval Office. We'd be sitting pretty today, I'll tell you. Carter could be the real president and Nixon could be the television president.

Maybe Carter should practice saying "I-am-not-a-crook" and try dabbling a bit of artificial perspiration on his upper lip. He has to do something. Because if he were a show on ABC, he would have been canceled six months ago.