It ought to be the law that before any economist of the Big Picture school is allowed to construct his or her macro model to explain so bloodlessly exactly what happened to this sad and scenic town on the Mahoning River he must first spend a month here.

Let the visitor walk by the Campbell Works of the Youngstown Sheet and Tube Company, where, on the day that people here still call "Black Monday," Sept. 19, 1977, 4,100 steelworkers were told for the first and last time that the mill was to be closed, that the jobs many of them had held for a quarter of a century were being abolished. Make sure that the visiting scholar sees the hurt and is exposed to the pain.

To understand that pain, it helps to think about what our jobs mean to most of us lucky enough to have them. Our jobs frequently define us; we are what we do. Our jobs give us more than incomes; they also confer status and self-esteem.

The loss of a job, especially a coveted industrial job such as that of steelworker, hurts. The steelworker was the contemporary counterpart of the American cowboy. He used and tested his muscles daily. He worked with danger and he worked hard -- no three-hour lunches with clients or customers.

In October 1984, in the second year of the recovery, unemployment here, according to a survey of 4,000 people by Youngstown State University's Terry Buss, is close to 30 percent. When Franklin D. Roosevelt became president in 1933, unemployment was 25 percent.

In the three-county area around Youngstown there are 40,000 homes for sale, and nobody to buy them. So much for all that cheerful advice about just picking up and moving to where all those help-wanted ads are published. A lot of people have stayed here, hoping that each new rescue plan or political promise would somehow work so that they, too, might work again.

And because there are still a lot of people here -- although fewer than there were 10 or 30 years ago -- presidential challengers come to Youngstown, both to seek votes and to dramatize the failed economic policies of the incumbent administration. That's what Fritz Mondale was doing Tuesday when he spoke to a friendly 10,000 folks in the fieldhouse on the campus of Youngstown State.

Mondale was good, but not as good as the 1980 challenger who blamed the suffering on "the failed Carter economic policies." Those policies, Ronald Reagan told the people of Youngstown, included Carter's "increased federal regulation," which brings with it "the cost of complying" that "diverts money that could otherwise be spent modernizing and improving plants and equipment." Bravely, that year's challenger confronted the Democratic president: "I say, let Jimmy Carter come to Youngstown and explain himself to you. Let him come here and listen to the tales of misery, of lack of work. . . ."

Ronald Reagan has had four years to wield his machete against the jungle of overregulation to which he attributed Youngstown's plight. He has had commissions and leading business executives to recommend just how quickly and completely government could be gotten off the backs of American producers.

Today, Youngstown is wiser and sadder. In the words of Pat Fleming, 36, a lifelong resident and vice principal of Ursuline High School (where 15 years ago the senior class numbered 500 and this year 201): "First comes helplessness, followed by hopelessness and then apathy."

Pat Fleming stays here by choice. Her friends and family are here, her roots. But that's not the case with Youngstown State student Walt Bedich, 22, who plans to move to Florida in December after he gets his degree in police science. Bedich will vote for Reagan, because "it's only a matter of time before he brings the economy back."

At 36, Ray Archer is one year away from a degree in transportation, which makes some sense, because Archer, the father of two boys, spent 16 years on the railroad before being laid off when the mills closed. He has already tried Florida, but he could not sell his house here, so he returned. Archer remembers that Jimmy Carter was in the White House when the closings started, and he blames Carter for doing nothing then. He, too, will vote for Ronald Reagan on Nov. 6.

The biggest sign in the field house read: "Mondale -- Man of Iron; Ferraro -- Woman of Steel." The Democrats will carry the Mahoning Valley. But whoever is president ought to be required to come here and see the pain and to try to do something to stop it. It's a human tragedy.