On this, the real New Year, when the country is going back to school or back to work after the summer respite, politicians do what they do best: they go back to running for office.

Once the Labor Day weekend is out of the way, it becomes impossible to pretend that the race for the presidency has not begun. This space will undoubtedly be filled with frequent (and erroneous) calls about who is leading and who is moving up on the outside.

In what may be the last calm moment for some time, I tried to ask myself what this election is about. What is it that the country needs to know about these men and their plans? What questions must we resolve about ourselves?

This year will not, I think, be dominated by a struggle between the generations. That fight is coming. But President Reagan is giving old age a new definition. And despite Sen. Gary Hart's efforts to ignite the impatience of those who have come of age since the '60s, one hears few spontaneous expressions of his belief that, "They had their turn; now it's our turn."

Nor, I think, will the campaign be a test of values of character, as it was in 1976, when the unstated test for all the presidential hopefuls was to see who could best complete the sentence, "Unlike Richard Nixon, I am a man you can trust with the authority of the presidency, because . . ."

President Reagan's personal character is unblemished in his third year in office. But Ronald and Nancy Reagan cannot project any more solid, decent, small-town, middle-class American values than do high school sweethearts John and Annie Glenn or the ministers' kids, Walter and Joan Mondale.

Neither is this campaign likely to turn on the question of who can best manage the government and the nation's affairs. There is no "mess in Washington," in the sense of scandals or gross incompetence pervading the scene. There is, instead, the usual mixed picture of well-run and badly run departments and the constant struggle for coordination and cohesion at the White House level.

Reubin Askew enjoyed greater respect from his peers as a governor than Reagan did and maybe had a better record of accomplishment for his state. Alan Cranston and Fritz Hollings have been powerful senators respected for their energy, their intellects and their political skills.

But while Reagan's record will surely be an issue, as an incumbent's always it, it will be difficult for any of the Democrats to prove that he is inherently more qualified to be president than the man who is president.

Policies will be important. The economic, social, defense and foreign policy changes Reagan put through in his first eight months in office-- even though softened a bit subsequently--represent the most significant shifts of governmental direction in a generation. This campaign will be a time of judgment on those changes, but not in the way many of us first thought.

Even before the current recovery demonstrated that the severe recession of 1981-82 was part of a worldwide cycle, not primarily the result of Reaganomics, voters of this country were rejecting the search for short-term scapegoats.

Voters I have met this year are thinking of long-term causes and effects. They see the nation undergoing a major economic transition, and they will judge Reagan's policies-- and the Democrats' alternatives--by what they think those policies will mean for them and their children's future. That is why education as well as arms-control are important issues, along with inflation, unemployment and protection against illness and the loss of economic security in old age.

Beyond those issues, there is a bedrock question to be answered in the coming campaign: whether we as a nation will meet these challenges as one people, resolute and self-disciplined, or as a quarrelsome gang of squabbling factions out to get whatever we can for ourselves.

For Reagan, the question arises in the form of the "fairness issue." Many voters wonder whether his vision of America really includes women, minorities and those who lose out in the struggle for economic survival. For many, if not all, of the Democratic contenders, the question comes in the form of "special-interests" influence. Voters wonder whether Reagan's rivals have such large political debts to the organized constituencies so influential within the Democratic Party that they cannot govern in the national interest. The question of whether we are one people or many will test the nation as much as those who would lead us. Its presence gives a special dimension and significance to the coming campaign. What now begins can be a time of reckoning for the United States--and not just a time for counting votes.