Imagine -- no questions, please--that peace and democracy reach Central America by nightfall. The region beds down to bliss, right? Wrong. It is already being savaged, as is most of Latin America and the Caribbean, by a veritable tidal wave of human beings demanding bread, work and dignity-- the components of a better life.

One knows all of this, of course, in some easy, unfocused, inattentive way. It is familiar. It is, well, kind of dull, not nearly so rewarding to politicians or journalists as the pulsing issues of guerrillas, missiles and the rest. Anyway, it's being worked on, or it's not being worked on-- does it really matter? Anyway, they're all down there, south of the border.

Except they're not all down there, not any more. They--the overflow, the desperate, the go-getters--are increasingly up here. The questions posed to Americans by this movement are no longer seen as the exclusive concerns of border residents and policy specialists. Bruce Chapman, the census director, collected a table-full of informed insiders and curious outsiders the other night to stir the brew.

The main thing I got out of dinner was the sense that long after war and revolution stop pushing political migrants out of Central America, harrowing distress across the region will be pushing out economic migrants. It's simple: the people are there and the jobs aren't.

Had you heard the good news, spread widely on the wings of a United Nations report last year, to the effect that birthrates are down in the poor countries and the population bomb is fizzling? Rates are coming down in some Third World countries, but we know how many people are coming onto the job market in this century--they are already born--and relief is not in sight.

Robert W. Fox of the Interamerican Development Bank puts it this way: to soak up new job-seekers, Latin America and the Caribbean must create in every remaining year of this century 4 million new jobs--twice the number that the American economy, which is five times bigger, created each year in the 1970s. Read it again and weep.

The Census Bureau reported that our 1980 census had counted some 2 million illegal aliens, almost half from Mexico. Discussion waxed hot on how many the census had not counted. The view was expressed that there is both less illegal immigration here and higher economic growth in Latin America than most people think, and therefore we have a bit of time, but this view did not seem to make it far around the table.

It is the received wisdom now that the United States cannot simply go with the illegal flow, whatever it is, but must take command of its own borders. This is the common impulse behind the immigration reform movement, otherwise composed of diverse political and ideological strains. A decent bill failed last year and another try is currently being made.

Development, almost everyone agrees, is the better answer, the necessary anwer, the right-thinking answer. From there the argument proceeds to questions of what economic system and what special techniques will produce the best results. You will not be surprised that a number of people at our dinner felt that the state's hand on a national economy--Mexico was cited as Exhibit A--is a dead hand.

One new idea leapt out. It came from demographer Fox, who juxtaposed development as a strategy to "accommodation." It means bowing to the population wave and the shortage of resources, setting aside the hope of lifting people out of poverty and instead undertaking just to "accommodate" them: providing minimal services--water, electricity, perhaps sewers--in designated areas of the exploding cities and parking people there.

The countryside corollary would be to set aside agrarian reform, which aims to raise up peasants and keep them on the farms, and to promote capital-intensive farming, whose results are to grow more food and to propel more people into the cities.

A shocking, manipulative, anti-democratic social science idea? Or a frank description of an approach that is already being quietly and widely followed, notwithstanding the difficulty the politicians would have in admitting it? How much easier it is to think about guerrillas.