Here we go again. Now it's the Reagan's turn to stand up for their family portrait on the podium and in the press. And now it's our turn to hear again that the sum of the Reagan parts do not add up to a whole.

Digit by digit, here is the rundown.

The "family" consists of one man, with four children -- three biological and one addopted -- from two marriages.

The second wife, Nancy, was the only child of a mother who was divorced in her infancy. The four children have only two things in common: they are all college dropouts and have all dropped in different directions rather far from the family tree.

Maureen, 39, has been twice divorced, is an ERA organizer and is an actress.

Michael, 35, has been once divorced and sells gasohol and races boats.

Patricia, 27, is a rock musician, composer, actress with an anti-nuclear bumper sticker on her car and a live-in-man in her past. Her song of the moment is, appropriately enough, "No Place Left to Hide."

Ron, 22, is a ballet dancer, who lives in New York with his woman friend.

In short, the family that took center stage Wednesday night was not quite as vintage perfect as the family that took center stage here Monday night, the Osmonds.

The Reagans have lived through the normal difficulties and estrangements of divorce and remarriage, and the normal growing pains of adolescence and rebellious adult children.

Now, none of this would be surprising or certainly shocking, except for the fact that the Reagan people have set themselves up as defenders of the Ye Olde Time Soda Shoppe family life.

So there are two schools of thought on why Reagan is preaching something entirely different from what he practiced. The first, The Conspiracy Theory, is that the man is a rank hypocrite playing to the audience holding tickets on the right side of the theater or, in this case, the right of the Joe Louis Arena. The second, The Honest Confusion Theory, is that the Reagans are a walking expression of ambivalence laced with a shot of denial.

Being of benign mind and body, I vote for the second theory.

It seems to me that any number of people have been through earthquakes in their private lives that haven't even made a crack in the walls of their philosophy. They hang onto their ideals as if they were the reality, and reguard any personal deviation like a bad accident. They prefer to forget that it happened.

Ronald Reagan is hardly the only man who believes in the permanence and sanctity of marriage, even in his second permanent marriage. Nancy Reagan is hardly the only woman who prefers to forget the woman before her. Nor are they the only people who believe in the closeness of family life, while experiencing distance with their own children. After all, nostalgia grows out of a sense of loss, not of fulfillment.

The nostalgia constituency is always greater than the number of people who are actually living the lives of the Waltons. It's part of the tension in millions of us to fill and fit both our old ideas of how we would live and how we do live. It's the tension between the ideal of stability and the reality of "accidents."

The only real tradition in family lives is the notion of a tradition, an ideal past in which values were passed down from one generation to the next as easily as pocket watches.

Reagan, for example, looks back to his own parents' lives as a time of stability and caring. But his parents' marriage, between a Catholic and a Protestant, must have unsettled his grandparents. In turn, surely, Reagan's divorce startled the older couple in Illinois, and Patricia Reagan's live-in mating startled Ronald and Nancy.

There is a curious pattern by which each generation redefines the traditional, while believing in it. A pattern by which each looks back on the last with nostalgia and forward to the next with anxiety.

"I don't think any of us is doing anything so alarming," said Patricia Reagan. And she is right.

The Reagans up there on the platform were a crazy-quilt pattern of reconstituted family life. They had been through change and had struggle to accept their distances and differences while remaining a "family."

They are like a lot of us. But I wonder if they know it.