THERE WILL BE another presidential debate tonight and we, The People, would be blessed beyond measure if the candidates would hew to Adlai Stevenson's admonition many years ago: talk sense.

It is not cynical to wonder if that is possible. Popularity is a basic principle of our political system and sensible talk is often unpopular.

If, for example, it is sensible to question and rethink the viability of the present Social Security system, is it possible for a candidate to say that out loud? Obviously it is not possible in 1984.

If it were sensible would a president or a presidential candidate dare say, "I really have no answer for the problems and hostilities in the Middle East and may never find such an answer"?

Of course it is true that what appears sensible to one of us is intellectual folly to another. But it is never folly in a political season to examine the assumptions, as opposed to the assertions, of those who seek to lead.

Our attention would be caught tonight if the debaters were to examine their assumptions about the power and capacity of the United States to manage the affairs of the world.

We have roughly 5 percent of the world's population and 25 percent of its wealth. Can we, with such substantial but still finite resources, fulfill global military commitments which the present administration defines as the ability to "meet any contingency" and the Democratic candidate defines as the "ability to defend American interests in the world"? Which "contingencies," which "interests"? If, as the candidates tell us, Central America is "vital" to our interests, are they willing to fight for it?

There are economic assumptions not undeserving of examination. Our economy is a remarkable engine, producing a gross national product of $3 trillion. Can it, however, sustain a national debt that approaches $2 trillion and grows by nearly $200 billion annually and at the same time provide major underpinning for the $800 billion debt of the developing nations of the world? And can we, simultaneously, continue to absorb international trade deficits in excess of $100 billion a year, deficts that threaten soon to make of us a debtor nation? Do we, specifically, erect protectionist walls, or do we -- because of the strength of the dollar abroad -- continue to export jobs through the loss of foreign markets for our manufactured goods?

Such questions are the sort one expects of bookkeepers; they take no account of the idealistic assumptions that infuse many of our policies, our sense of place and mission in the world. This idealism, in differing ways and in differing manifestations, is expressed by both candidates. They see or would like to see an America that contributes mightily to the amelioration of poverty, hunger and social injustice here and on other continents. And how is that to be done and how soon and at what cost? At home, 10 to 15 percent of our people live below a defined poverty line. Abroad -- in Africa, Latin America and elsewhere -- the numbers are in the hundreds of millions. Is our idealism consonant with our capacity to achieve our goals?

All things may be possible -- social reformation, global military might, economic and financial stability. But does the possibility hinge on sacrifice, a word and an idea that enjoys little currency in the political dialogue of 1984? President Reagan promises to do all things without an increase in taxes. Walter Mondale promises to do all things with a modest sacrifice, higher taxes primarily on the "rich," meaning the less than 5 percent of the population with incomes in excess of $60,000 a year. Are these assumptions valid, can the United States do it all and sacrifice little or nothing Or are such assumptions relics from an easier past?

The pride and optimism of our people and of our politicians are enduring elements in the character of the nation. We The Questions That Need Debating Our Future Depends On Matters That the Canidates Never Candidly Confront

By Richard Harwood

THERE WILL BE another presidential debate tonight and we, The People, would be blessed beyond measure if the candidates would hew to Adlai Stevenson's admonition many years ago: talk sense.

It is not cynical to wonder if that is possible. Popularity is a basic principle of our political system and sensible talk is often unpopular.

If, for example, it is sensible to question and rethink the viability of the present Social Security system, is it possible for a candidate to say that out loud? Obviously it is not possible in 1984.

If it were sensible would a president or a presidential candidate dare say, "I really have no answer for the problems and hostilities in the Middle East and may never find such an answer"?

Of course it is true that what appears sensible to one of us is intellectual folly to another. But it is never folly in a political season to examine the assumptions, as opposed to the assertions, of those who seek to lead.

Our attention would be caught tonight if the debaters were to examine their assumptions about the power and capacity of the United States to manage the affairs of the world.

We have roughly 5 percent of the world's population and 25 percent of its wealth. Can we, with such substantial but still finite resources, fulfill global military commitments which the present administration defines as the ability to "meet any contingency" and the Democratic candidate defines as the "ability to defend American interests in the world"? Which "contingencies," which "interests"? If, as the candidates tell us, Central America is "vital" to our interests, are they willing to fight for it?

There are economic assumptions not undeserving of examination. Our economy is a remarkable engine, producing a gross national product of $3 trillion. Can it, however, sustain a national debt that approaches $2 trillion and grows by nearly $200 billion annually and at the same time provide major underpinning for the $800 billion debt of the developing nations of the world? And can we, simultaneously, continue to absorb international trade deficits in excess of $100 billion a year, deficts that threaten soon to make of us a debtor nation? Do we, specifically, erect protectionist walls, or do we -- because of the strength of the dollar abroad -- continue to export jobs through the loss of foreign markets for our manufactured goods?

Such questions are the sort one expects of bookkeepers; they take no account of the idealistic assumptions that infuse many of our policies, our sense of place and mission in the world. This idealism, in differing ways and in differing manifestations, is expressed by both candidates. They see or would like to see an America that contributes mightily to the amelioration of poverty, hunger and social injustice here and on other continents. And how is that to be done and how soon and at what cost? At home, 10 to 15 percent of our people live below a defined poverty line. Abroad -- in Africa, Latin America and elsewhere -- the numbers are in the hundreds of millions. Is our idealism consonant with our capacity to achieve our goals?

All things may be possible -- social reformation, global military might, economic and financial stability. But does the possibility hinge on sacrifice, a word and an idea that enjoys little currency in the political dialogue of 1984? President Reagan promises to do all things without an increase in taxes. Walter Mondale promises to do all things with a modest sacrifice, higher taxes primarily on the "rich," meaning the less than 5 percent of the population with incomes in excess of $60,000 a year. Are these assumptions valid, can the United States do it all and sacrifice little or nothing Or are such assumptions relics from an easier past?

The pride and optimism of our people and o express it all in the slogan, "Number One," a slogan that, in many ways, is true and realistic. In another sense, however, it is archaic.

Consider how others see us today, specifically a Soviet historian and propagandist, Georgi Arbatov:

"After the Second World War, the United States entered upon an unusual historical period. Your major adversaries had been routed. Their economies were in ruins. Your allies, including the Soviet Union, were on the ropes, devastated by war.

"You emerged from that conflict less hurt and damaged than any of the other combatants. You enjoyed economic superiority in the world, as well as military superiority. It began to look to many Americans that the time of Manifest Destiny had arrived -- the American Century -- and that you could either stamp over people or buy them. You assumed you would have perpetual eminence. Then, things began to change.

"You lost your nuclear monopoly. You began to meet with strong economic competition -- from Japan and Western Europe, for example. By the end of the 1960s you were at a crossroads. You had to find a way out. You had to find ways to adjust to the new situation, to new forces in the world which caught you up in Vietnam and Iran. The world had changed since the end of the Second World War and that era will not be repeated. It is a new world."

In this new world, the United States remains optimistic and strong. Its political system and its political leaders must embody those qualities. But they should, at the time, be clear eyed about the assumptions on which their policies and rhetoric are based.

The lobbies and interest groups that seek to manipulate the political process may demand pablum. But that is no proper diet.

John Kennedy, who is now ridiculed as naive by many statesmen and intellectuals, spoke in his inaugural address of trumpets calling us again to assume the burden of a "long twilight struggle . . . against the common enemies of man: tyranny, poverty, disease and war itself." He was saying that there is no free lunch, that military commitments are not bloodless, that economic commitments are not painless.

"What does concern me," Adlai Stevenson said in 1952, accepting the Democratic nomination for president, " . . . is not just winning the election, but how it is won, how well we can take advantage of this great quadrennial opportunity to debate issues sensibly and soberly . . . .

"Let's face it. Let's talk sense to the American people. Let's tell them the truth, that there are no gains without pains, that this is the eve of great decisions, not easy decisions . . . ."

That is what we want from the candidates in 1984: tell the truth and talk sense.