A noose is tightening around Latin America.

The $360 billion in debt the countries have taken on -- most of it in the halcyon days of the 1970s -- poses not only a severe constraint on their current growth but an even more imposing obstacle to future development.

Three years after the onset of the debt crisis, the economic and social future of the region looks little better than it did in August 1982.

With varying degrees of commitment, the countries have put the clamps on their economies while they try to earn the dollars needed to pay their foreign debts.

Unemployment has mounted. Poverty has increased. In many cases, the countries have taken food from the mouths of their citizens in order to sell it abroad.

But the promise that things would get better if only they went through a few years of pain now appears to be a hollow one.

The bigger debtors such as Mexico and Brazil have managed to pay their international bills on time -- lessening the threat that the Latin American debt burden would destroy the international financial system. And economic conditions in most countries have improved a little since 1983, when most experienced wrenching recessions.

But whether measured in the bloodless statistics cited by economists or the flesh-and-blood tableau, economic and social conditions in Latin America are no better than they were a decade ago and desperately worse than they were in 1980.

More frequently and more forcefully, leader after leader is beginning to question the tactics advocated by the International Monetary Fund, the multinational financial rescue agency that spearheaded the efforts to manage the Latin American debt crisis.

When banks stretched out debt repayments and added a little fresh money, and when the IMF and the countries agreed to stiff economic programs, the hope was an eventual return to at least a semblance of normal economic growth.

"It is clear that what we all expected hasn't happened," said Enrique Iglesias, foreign minister of Uruguay and one of Latin America's leading economists.

The prices of the raw materials -- mainly minerals and foodstuffs -- that the countries must export to earn dollars have declined steadily. That means the countries must export increasing amounts of products merely to earn the same amount of dollars.

The fresh loans and investments have been far smaller than anticipated and probably will be even smaller in the future.

And the citizens of the debtor countries, who were supposed to regain their faith in the homeland, remain skeptical. As a result, dollars that are desperately needed at home continue to "flee" Latin America for havens such as the United States, although in smaller quantities than before.

"I've got some money in Washington," a top Argentine economic official said. He said he believes that a tough program inaugurated last June by President Raul Alfonsin will turn Argentina's economy around, but he conceded that he is not sure enough to bring back his deposits.

Not all of the blame can be laid on the international economy, however. For the most part, Latin American countries have not made a serious effort to change their own internal policies that hinder economic development -- such as dismantling huge state enterprise systems that drain vitally needed government resources, changing restrictive rules that hamper foreign investment or convincingly attacking the high inflation rates that discourage domestic investment.

But many countries have made painful short-run efforts to enable them to pay their debts, including sizable currency devaluations to encourage exports and discourage imports. Those policies in many cases have encouraged farmers to produce crops they can sell abroad rather than crops that will be sold at home. Mexican farmers are producing sorghum and neglecting corn. Brazilian farmers can earn more selling soybeans than they can raising rice or beans. Feeling of Betrayal Grows

Leaders of these countries, many of whom have put their economies through grinders, feel betrayed by industrialized countries -- especially Europe and Japan. The debtors have been told they must export more -- not only to earn dollars to pay their debts but to come up with a little more to buy the imported items such as components and spare parts that are vital to many of their domestic industries.

But they are finding increasing resistance to their exports by those same developing countries. The European subsidy to its cattle raisers exceeds the cost of production in Argentina. The world price for sugar is 3 1/2 cents a pound, but Europe pays its farmers 21 cents a pound to produce it.

The United States has been more open. Its imports from the area have risen 32 percent in the same period. But products such as shoes, steel and copper have become the subject of protectionist complaints in this country.

"If we are going to pay our debts, we must export," said Ulysses Gemarais, the speaker of the Brazilian House of Representatives. "Dead men don't pay."

As incensed as they are at protectionism, Latin American leaders are weary of what they see as a lack of fresh ideas at the International Monetary Fund, which has lent small amounts of money in return for changes in economic policies and, more important, has provided the imprimatur that commercial banks required before they reached new loan agreements with the debtors.

Even some officials of multinational banks are becoming uncomfortable with the IMF's insistence on continued austerity.

"I think the IMF has only got one book on the shelf," said a top executive of a major U.S. bank.

Major Latin American leaders are not in revolt yet. But they are becoming increasingly critical of what they consider to be the continued IMF reliance on austere policies that do not appear to be working. Yet the IMF, as recently as last week, reaffirmed its belief that nations must take harsh anti-inflation measures, cut out government budget deficits and run bigger trade surpluses as a precondition to a return to health.

It has suspended lending to Mexico, which not too long ago was considered the model debtor, and Brazil, which has managed to ring up stunning trade surpluses, because the countries have fallen out of compliance with the economic programs they promised to follow. Rethinking the IMF's Role

Mexican President Midquel de la Madrid, the champion of the types of austerity advocated by the IMF, began to rethink austerity even before the IMF's action. The Sept. 19 earthquake that shattered Mexico City is sure to cause Mexican officials to reconsider the tight budget they have been following in recent months. But it also may trigger emergency loans from the United States, other governments and multinational institutions such as the IMF that will put the country in a better cash position than it was before the tragedy.

New Brazilian President Jose Sarney has publicly pledged that he will not sign an agreement with the IMF that would throw the Brazilian economy into another recession. Brazil's central bank president, Fernao Bracher, has argued that his nation's domestic policies should be of no concern to the IMF so long as they do not threaten Brazil's ability to pay its debts. Unlike most of its neighbors, Brazil has increased its exports mightily and earns more than enough dollars to pay its debts and buy a sizable portion of the imports it wants.

Alan Garcia, the new president of Peru, has threatened to pull out of the IMF and has said he will negotiate with Peru's commercial bank lenders but will not sign a pact with the IMF as a precondition. He also has said that Peru cannot afford to pay more than 10 percent of its export earnings to pay its debts.

In the last two years, three Latin American nations -- Argentina, Brazil and Uruguay -- have turned from military dictatorships to democracies. In Peru, a civilian government handed over power to another civilian government for the first time in decades.

In private and in public, newly elected leaders such as Sarney and Argentina's Alfonsin warn that democracies must demonstrate that they can perform better than the military dictatorships they replaced. Latin American officials complain that, so far, they have received little more than vague promises of support for democracy and none for their economies.

"When we ask Europeans what we should do, all they tell us is 'pay your debts,' " said Adolfo Gass, chairman of the foreign relations committee of the Argentine Senate.

There is some evidence that the United States, at least, is beginning to worry about the implications of the lack of economic progress in Latin America. Secretary of State George P. Shultz and Treasury Secretary James A. Baker III apparently are in agreement that the short-term austerity measures advocated by the IMF are outliving their usefulness, and they are working on a plan that would pump more long-term funds into the region.

Not only might left- or right-wing nationalistic explosions pose severe threats to U.S. security interests in the hemisphere, the continuing economic problems in the region are a major burden to the U.S. economy. The United States is the biggest export market for Latin America, and Latin America is a major buyer of U.S. products, as well.

Chemical Bank economists estimate that as many as 800,000 U.S. workers are unemployed because of Latin America's inability to buy U.S. products.

Nevertheless, the Reagan administration is wary of any plan that would require big U.S. expenditures and that might be seen as a bailout of multinational banks -- which hold about $220 billion of the region's $360 billion in debt.

Furthermore, there seems to be little anyone or any country can do to reverse the fundamental plight facing Latin America: The world no longer wants or needs -- at least in the same quantity and at the same prices -- many of the raw materials the region long has relied on to earn foreign income.

"There are important structural changes in the world economy," said Cesar Atala, Peru's minister of industry. "New technologies and changes in industrial economies have changed the world's demand for materials that we traditionally export."

Except for oil-exporting countries, Latin American debtors have seen the buying power of their exports deteriorate steadily in the last 15 years, punctuated by a brief surge during the world inflation of the late 1970s.

"It is not only a temporary change in supply and demand," according to Uruguayan Foreign Minister Iglesias. "In many cases like copper, it is absolute, and in other cases, Latin America is facing competition from the north. It is a real revolution in trade."

Iglesias said Latin American nations must adjust their economies and build new industries that will enable the to find new export markets to replace those that are declining. Needed: Time and Money

"We cannot adjust without time and capital," he said.

Both of those are in short supply in Latin America.

Augusto Ramirez Ocampo, foreign minister of Colombia, said that the level of social unrest varies from country to country, but it is doubtful that most governments will be able to contain that unrest for much more than two years.

The flow of outside funds into Latin America is declining and domestic savings have been cut by severe recessions and continued lack of confidence in the future. Already the countries are paying more to the outside world than they are receiving and in the next few years face the prospect of having to repay the IMF for the loans they received in 1983 and 1984.

Except for Brazil and Colombia, most countries misused the funds. Far too often they used their borrowing power to finance deficits in burgeoning federal budgets, to subsidize consumption, to build unrealistic or inefficient projects, or to satisfy the demands of their own citizens for foreign exchange.

Argentine economist Jorge Dominguez estimated that Argentine citizens have nearly $35 billion on deposit abroad. The country's foreign debt is $48 billion.

Nevertheless, economists and Latin American officials say the picture is not entirely bleak:

*Many countries have managed a return to modest economic growth in the last 18 months. But the pace of that growth is constrained by the need to pay interest on debt.

Not too long from now, the idle industrial capacity in Latin America will be used up and the shortage of dollars will hinder the countries' ability to expand their industries.

"When an economy is growing, the population sees some hope," said Luis Paulo Rosenberg, chief economic adviser to Brazilian President Sarney. Unless that hope is totally extinguished, the countries may be able to keep a lid on social problems while seeking more permanent solutions.

*The announcement by the United States and four other top industrial countries that they will take concerted efforts to reduce the value of the dollar and reduce the $150 billion U.S. trade deficit should make Latin American exports more competitive pricewise. Latin American countries have keyed their exchange rates to the dollar. If Europe and Japan stimulate their economies as promised, there should be an increase in demand for some Latin American products.

*Countries such as Argentina, Brazil and Mexico are talking about taking steps to reduce their bloated state sectors and slowly open their economies to the types of international competition that will make domestic industries more efficient and better able to export.

Serious structural reforms in Latin American economies, as in any economy, are a long-term proposition. For economies that have been struggling for three years, short-term progress is needed, too.

Presidents flail the debt in public utterance after public utterance. Polls across the region show that citizens think the foreign debt is the most pressing issue of the day.

If the debt issue blows up, the biggest loser could be the United States -- whose security and economic stake in the region is large.

It doesn't matter what the facts are, whether the United States is fighting to keep open markets and buying large quantities of Latin American exports while Europe and Japan are doing little more than paying lip service to the region, cautioned Dante Caputo, foreign minister of Argentina.

"Right or wrong, the debt equals the United States in the eyes of the layman," he said.