"Pay no attention to that man behind the curtain." The Wizard in "The Wizard of Oz"

Very probably, 1983 will go down in history as the last year of President Reagan's honeymoon with television, the year his version of "The Honeymooners" expired.

Reagan's honeymoon with Congress is over, his honeymoon with the press is pretty well kaput. It could be that these relationships grew shaky because it was perceived Reagan's TV show was beginning to falter in the ratings. Whatever, the medium that he understands so well, so instinctively, is Reagan's last honeymooner, and tonight he will use it to kick off a new public relations offensive. Live, from the glamorous U.S. Capitol Building--it's President Reagan and . . . "The State of the Union"!

An administration's fate can now be said to rest on how great a communicator "The Great Communicator" really is. Actually, he has to do more than communicate. He has to do a soft-shoe, a buck-and-wing and a few convincing choruses of "Forget Your Troubles, Come On, Get Happy" as well. And yet even all of that may not be enough.

There has been much talk in recent weeks of Reagan's detachment--from his staff, from the office, from the issues, even, perhaps, from the realities of what is happening in the country. But Ronald Reagan feels no detachment from the camera. He is at his most comfortable with it. He can't wait to get in front of it again. It's his security blanket.

What Ronald Reagan the attractive, illusory figure on TV must contend with now is not only the probings of the media and the nagging of political opposition; there is also the record of his presidency to be bucked. His future television appearances will be designed to refute--with symbols, charisma, wishful illusion and the showmanship he learned in Hollywood--his own two-year record and the economic conditions of the country.

Can it be done? The networks show pictures on their nightly newscasts of the unemployed standing in line for food, of farmers battling the banks that are foreclosing on their homes and their land, of homeless souls sleeping in cardboard boxes. The White House mounts a counteroffensive. It dispatches President Reagan to a school attended by black children and has him speak to them and play with computers. Fighting sad pictures with happy pictures is one thing. Fighting grim reality with happy pictures is a harder trick to pull off.

If the Reagan administration were a television series, it could be called "Fantasy Island."

The State of the Union address tonight can be seen as the kickoff in what may be the most furiously fought battle of imagery in the country's history. For the Reagan White House, there are two potentially ruinous complications: Americans don't see the unemployed and the impoverished only on television; they see them in real life, and they may even count themselves among them. And, sadly, there are indications that the White House is fighting the battle of the image with much more passion and dedication than it is fighting the battles to improve economic conditions for those most debilitated by them.

In other words, it is trying to pull off a colossal victory for mind over matter.

The one presidential image Ronald Reagan still has not been able to master--and he may not even be inclined to bother with it--is the image of a man passionately trying to pull things back together, a man with his sleeves rolled up (even, just a man with his suit coat off), working all hours of the day and night on the country's troubles, and thus rallying and galvanizing rich and poor into action, and a united front, the way FDR did.

That persona just isn't there, in any of those cheerful, dapple-cheeked images.

Reagan is as telegenic as ever when speaking to the camera or, as he did last week, participating in such media stunts as an ingratiating half-hour with student leaders from around the country on C-SPAN, the cable satellite public affairs network. After the questioning was over, Reagan stood up, a technician approached him, and Reagan said no, he didn't want to take off his microphone just yet, he had a few more words to say to the students. As he has countless numbers of time, the president looked like a great guy. He looked, as they said in the '40s, swell. But putting two years of all the TV images and situations together, and including among them innumerable fleeting glimpses of the president and first lady heading for a helicopter and another vacation, one still may get the impression of a president who is little more than a guest star in his own administration.

Sometimes news footage of the president signing a bill or shuffling papers around on his desk looks like an outtake from a movie; Ronald Reagan looks like an actor playing the president of the United States. He plays the part the way Fred MacMurray played Dad on "My Three Sons." It worked for two years because it generated plenty of good faith, and people said, "He's a great guy, let's give him a chance," but can it work when the chips are most emphatically down and there are 12 million unemployed who see themselves running out of chances?

In the months of television ahead, Reagan's advisers will try to scuttle the images that suggest a President of the Rich and present Reagan in situations that support the illusion of a concerned statesman and leader. Viewers will see less news footage of fancy-shmancy black-tie dinners because the White House will try to give fewer of them. White House insiders are shuddering even now at the impression that will be made by news pictures of Nancy Reagan standing with Queen Elizabeth II aboard the royal yacht Brittania when the Queen visits the United States late next month.

They'll have to send the president on a walking tour of Watts to offset that one.

The big question now is not whether the president's relationships with Congress or even the supposedly almighty "media" will deteriorate further. It's the question of his relationship with the American people through the manipulative medium of television that matters. This is a president who was made by television and who could be unmade by it. Indeed, in the future, the Reagan administration may be looked back on the way a half-forgotten television series is looked back on, as something languishing in the mists of memory alongside "The Montefuscos" or "Me and the Chimp." Something like, "The Reagan Years."

A recent glossy report issued by the Republicans, "The Reagan Presidency, A Review of the First Two Years, 1981-1982," reads like a promo for a TV series, or a "treatment" for one, to be submitted to network executives in the hopes of getting funding for production. On one page, "Ronald Reagan The Communicator," it is boasted that Reagan's Nov. 18, 1981, speech at the National Press Club "was beamed to 200 million people worldwide. It reached one of the largest audiences of any President."

That's like bragging of big Nielsens for an episode of "Dallas."

This is a presidency conceived in terms of television and designed for its demands. It goes back to before Day One, but on Day One, the inauguration, television directions were virtually written into Reagan's inaugural address. (The president listed various Washington monuments where cameras were stationed, and it was up to the networks if they wanted to cut to shots of them during the speech. CBS did.)

This White House has not, perhaps surprisingly, made a big deal out of alleged hostility from the allegedly liberal establishment press. For one thing, Spiro Agnew did the republic the disservice of making such gestures look suspect ipso facto. Last March, when President Reagan did venture a complaint or two about the heavy play that poverty was getting on the network newscasts, he was quick to retrench.

Privately, the president's advisers do view the networks as hostile--or two of the network news departments, anyway. ABC is thought to be gentlest on the administration, NBC is considered somewhere in the middle, and CBS is viewed as The Enemy. It is entirely likely that a new offensive against the network news departments will be mounted by the White House as those pictures of poverty proliferate. But it will have to be done very cleverly, because the one thing the president's men feel they can always fall back on is Reagan's so-far uncorrupted image of Mr. Nice Guy. The danger of tarnishing that gold medal was what inspired retreat from last year's attack on the networks.

Meanwhile, no matter how good Reagan looks on the air, Reagan's America seems bound to continue looking awful. In addition, relatively new technological refinements make it easier than ever for network news departments to pull from their video files tape of the president promising this, or that, or promising not to do this or that, and that can be used to make him look ridiculous when he neglects to stay his own course.

In the beginning, television loved the president; not only did the camera adore him, but even the network reporters seemed to be giving him an easy time of it as well. There are many reasons beyond, but including, Reagan's personal charm. One is Jimmy Carter. Anything would have looked good after that, but Reagan's grandfatherly pizazz seemed particularly invigorating. Much has been written of some imaginary "ideological mandate" that the electorate handed Reagan in 1980; the ideological mandate was: Everybody was fed up to here with Jimmy Carter and his simpering and they wanted him out. Lorne Greene might have made it under the same circumstances.

Reagan was a little like Professor Harold Hill in "The Music Man"; people, including media people, wanted to believe in him. They wanted to believe you could play the "Minuet in G" just by thinking you could (this was the essence of supply-side economics). But by the second year of the presidency, it still wasn't sounding much like Beethoven. Not even Irving Beethoven, the butcher. Now there are bound to be catcalls of "charlatan" and "fake." Whether or not Reagan can continue to dispel them with the strength of his television appearances remains to be seen, and tonight's performance is bound to be a bellwether one way or the other.

The horse race may all boil down to personality politics, but Reagan's advisers still have aces in the hole. If the House and Senate agree on a plan to save the Social Security system, as it is expected they will, the White House can take the credit for it, and President Reagan can announce it to the nation in a prime-time address. That feat can be combined with a hoped-for arms control treaty later this year to support an image of a dynamic presidency with solid accomplishments behind it, even if the economy is still a disaster.

The White House will launch a mammoth public relations campaign, starring the president, to put across the idea that these or some similar achievements are the result of his tireless labors in the nation's behalf. It'll take as many special effects as "Superman II," but it may look just real enough.

Still, there will be other factors besides news footage of bread lines to counter White House efforts to paint The Pretty Picture. After all, Reagan isn't the only politician in the world who's good TV. Now that Teddy Kennedy has officially announced he won't seek the 1984 presidential nomination, he is perhaps freer than ever to spearhead a dynamic, forceful, even exuberant opposition on nightly newscasts. John Glenn has been taking TV lessons and he already has the allure of a national hero going for him; Robert Dole is known for his witty remarks, and the cameras may gravitate to him, or to Senate Majority Leader Howard H. Baker, a hugely admired figure, as their attractiveness as 1984 candidates grows and Reagan's weakens.

Television news usually lags behind print in terms of context and general perceptions, and now that Reagan is being castigated by pundits and commentators in newspapers and magazines, the more aggressive TV reporters--ABC's Sam Donaldson at the White House, CBS's Phil Jones on the Hill, NBC's acerbic and sagacious anchor Roger Mudd--can be expected to turn more aggressive still. Essentially, the networks have merely been reporting, so far, on the print allegations that Reagan is the amazing invisible president. Eventually, they will generate their own reports, and commentaries, to that effect. Before this is all over, the president may have to call on reserves of charisma and camera presence not even he knew he had.

And if that effort is a success, if an administration can essentially fail the country, and its own promises, on the one hand, yet maintain the appearance of success through television on the other, then it will have been proven that we are even deeper and more irretrievably into the Image Age than furrow-browed deep thinkers in communications have already speculated we are. The question that may be answered by Ronald Reagan and his traveling television show is, in contrast to Lincoln's question of whether a nation can long endure " half slave and half free," whether an administration can endure half real and half unreal. Ronald Reagan could conceivably leave office the best-loved failure in American presidential history.

Dorothy: "You're a very bad man!"

Wizard of Oz: "Oh, no, my dear, I'm a very good man. I'm just a very bad wizard."