Argentina's latest financial travail is an unwelcome reminder to many Latin American leaders and diplomats that the Reagan administration seems much more concerned about two tiny nations in Central America than about the fate of democracy in the biggest and richest countries on the continent.

These Latin Americans grant that the United States is working with other countries to help Argentina once again hold off its creditors with emergency interest payments. But they are also convinced that President Reagan is much more concerned about "winning" in El Salvador and Nicaragua than he is about the fate of the largest democracies on their continent.

Argentina may well get past its latest crisis in relations with foreign lenders, but without much more help from Washington, what will its ultimate fate be? And what of Brazil, Mexico, Chile, Peru? The preoccupation with winning in the minuscule states of Central America could cause the United States to lose the countries that are far more important to its long-range interests in the region, they feel.

These leaders believe that current U.S. policy, focused on thwarting what the administration sees as the threat of communist-backed subversion in Central America and the Caribbean, is a classic example of what one diplomat calls "the United States chasing the wrong bouncing ball" in determining its Latin American priorities.

In this view, the future political and economic direction of Latin America will be determined not in the Central American isthmus but in the big countries of Latin America that have the size, resources or influence to have a regional impact, and perhaps ultimately to play an increasing role on the broader world stage.

That is the point made most insistently in interviews and discussions with a broad cross section of Latin politicians, bureaucrats and diplomats. In this country, it is echoed by many academic experts on Latin America and by representatives of U.S. banks and other businesses who see their interests increasingly bound up with the state of Latin America's economic health.

However, before these countries can provide meaningful leadership for an emerging Latin America, they must first grapple with formidible domestic problems that threaten to swamp the encouraging but still fragile trend toward democracy in much of the region.

The nature of these problems differs in each country. But almost all share a root in the staggering burden of debt now hanging over the region, which last year forced Latin America to export $27.6 billion of its sparse financial resources as payments to foreign banks.

To the debt-ridden governments of the region, this financial bind is a far greater threat to inter-American and global security than leftist revolutionaries in Central America.

But their pleas for a major and sustained U.S. effort to help them climb out of the economic quagmire has met with a response that the Latins regard as too little, too sporadic and too prone to emphasize the economic austerity nostrums of the International Monetary Fund, which often fan popular discontent with politically weak governments struggling to give democracy a chance. (In the latest round of Argentina's problems, compliance with the dicta of the IMF is again the key issue.)

The Latins do credit Washington with reacting swiftly to emergencies, but Argentina's Ambassador Lucio Garcia del Solar warns:

"Our countries are still choking on debt. That is a greater danger to the security interests of the United States than guerrilla wars in Central America because if the situation is not alleviated, the democratic presidents emerging in the biggest, most pivotal countries will be unable to counter the political consequences of debt.

"They will be vulnerable to surges of populism pushing them toward the extreme right or left. In some countries, it could mean a return to military dictatorship. In some, it could lead to resurgent leftist terrorism that will draw them into the East-West conflict. In the Andean countries like Colombia, Peru and Bolivia, there literally is a danger of the narcotics traffic becoming so important a source of national revenues that entire governments will be corrupted and come under the control of local drug mafias."

But, the ambassador concludes, "We are not getting this message across. The bottom line is that the U.S. government doesn't see the debt crisis as affecting the national security of the United States."

His gloomy assessment contrasts sharply with the Reagan administration's recent tendency to stress the optimistic view that Latin America is moving toward a new democratic stability.

"In the Western Hemisphere, over 90 percent of the population of Latin America and the Caribbean today live under governments that are democratic," Secretary of State George P. Shultz wrote recently. "After a long twilight of dicatorship, this hemispheric trend toward free elections and representative government is something to be applauded and supported."

A similar note was sounded in February by Elliott Abrams, the State Department's human rights chief who is about to become Shultz's assistant secretary for inter-American affairs. In releasing the department's annual reports on human rights conditions in 164 countries, Abrams cited the "very strong and impressive trend toward democracy in Latin America" as the most significant rights development of 1984.

Latin officials like Garcia del Solar agree that this is potentially a favorable trend for the United States. They note particularly that the region's most prominent new democratic leaders such as Mexico's Miguel de la Madrid, Argentina's Raul Alfonsin, Brazil's Jose Sarney and Uruguay's Julio Sanguinetti are essentially pro-American and eager for close cooperation with Washington.

But, while they are appreciative of the rhetorical support that U.S. officials have given to the spread of Latin democracy, they also warn that Washington, by its actions in Central America and its alleged inaction on the debt question, is making cooperation difficult. They argue that even if the administration achieves such Central American goals as overthrowing or intimidating the Sandinistas, it will have won only a Pyrrhic victory. The immediate gains would be offset by a sharp upsurge of anti-Americanism, particularly in the larger Latin countries where such U.S. tactics as economic embargoes and support of anti-Sandinista guerrilla forces are seen as a revival of "big stick" Yankee interventionism.

Except for Jose Napoleon Duarte in El Salvador and Roberto Suazo Cordova in Honduras, both fearful of Nicaragua and dependent on the United States for their economic survival, none of Latin America's democratic leaders has supported the main tenets of Reagan's Central America policies.

Some, like Alfonsin, have sought diplomatically to couch most of their criticism in indirect terms and occasionally have rebuked Nicaragua for such actions as President Daniel Ortega's visit to Moscow. But the harshest words of condemnation coming out of the Latin democracies has been directed at recent U.S. actions such as the economic embargo against Nicaragua and has tended to echo Mexico's charge that such acts are "economic coercion" incompatible with Latin efforts to bring peace to Central America.

Those making that argument include many who do not dispute that Nicaragua's Sandinista government is a revolutionary regime or that its most influential leaders are Marxists intent on aligning their country with Cuba and the Soviet Union. But they disagree with Washington about what long-range strategy would be most effective in preventing Nicaragua from becoming a base for subversion and forcing it onto paths less hostile to its neighbors.

Essentially, they argue that if the bigger countries can realize their potential for industrialization and a more competitive export posture, some of the resulting prosperity will spread to regional trouble spots like Central America by providing its tiny nations with new or expanded sources of trade, investment and assistance in their neighborhood.

And, if the smaller countries become more dependent on larger neighbors for economic well-being, they will also be more susceptible to the political influence exerted by their new partners. Thus, this theory concludes, a strong and democratic Mexico or Venezuela ultimately can be much more effective than U.S.-backed military solutions or embargoes in overcoming the social and economic inequities making Central America a target of subversion.

But that cannot be done by countries whose economic houses are in disarray. Even Mexico and Venezuela, the two countries cited by U.S. officials as making a good effort to extricate themselves from financial chaos have such massive foreign debts ($96 billion for Mexico and $35 billion for Venezuela) that many bankers and political observers doubt their ability to maintain unpopular austerity programs in the face of mounting domestic discontent.

Brazil, the world's largest debtor nation with a foreign debt of $100 billion, and Argentina, whose debt is $47 billion, are under constant threat of losing the IMF's financial help because domestic political pressures have forced them out of compliance with the economic austerity programs to which they agreed.

Chile, where a tough military dictatorship is able to ignore public pressures, has taken the steps mandated by the IMF to overcome its debt of almost $20 billion, but its economy continues to worsen because of depressed copper prices. Peru, with a $14 billion debt, faces such serious economic and political problems that bankers are beginning to question whether it can ever recover. Alan Garcia, who is about to become Peru's new president, has threatened to bypass the IMF and seek joint action by the Latin debtor countries to force a confrontation with their American bank creditors.

That is why so many Latin Americans warn that continued progress toward democracy and stability cannot be achieved unless it is backed up by a shift in Washington's priorities and allocation of resources. What they want was summarized recently by Abraham F. Lowenthal, professor of international relations at the University of Southern California.

"One of the greatest single challenges to U.S. policy during the next few years will be trying to help reestabish a viable international order," he said. "The aim of U.S. policy should be to help shape rules, procedures and institutions appropriate for a world in which political power and productive capacity are much more widely dispersed than previously, so that the worldwide recession can be ended; global trade can begin to expand again, and capital, technology and labor will again flow more freely in a growing world economy."

There is little hope of Latin America realizing anything like that in the foreseeable future. And Latin leaders are smarting over the fact that for the second year in a row, their plea for urgent attention to the debt crisis and other North-South issues was ignored by the annual economic summit of the West's seven principal industrial powers.

But, while comprehensive relief seems unlikely, the Latins argue that it is vital for the United States to help them with more limited steps. These include greater access to the U.S. market for their exports, exploration of ways to subsidize the enormous interest on debt service and supporting moves to have multinational lending institutions like the World Bank issue guarantees for borrowing from commercial banks and loan more money to countries seeking to make major changes in the structure of their economies.

"It's not enough for the United States to just keep saying 'Do what the IMF tells you' and let it go at that," one banker said. "Latin America is not going to continue exporting almost $28 billion a year to foreign banks without their being an increasingly unacceptable risk of defaults that could leave the international banking system in tatters."

Such a development probably would halt "the steady advance of democracy in Latin America" cited by Shultz. Instead, the United States would be far more likely to find itself confronting the scenario sketched by Lowenthal:

"The decline of U.S. influence in the Western Hemisphere will surely accelerate unless the United States sustains a major effort to help Latin American overcome the financial bind that ties their prospects to those of the United States. Otherwise, whatever his intentions and his efforts, Ronald Reagan could go down in history as the president who lost Latin America."