Thirteen days ago, acting on highly publicized and controversial orders from the State Department, U.S. representatives to the World Bank voted in favor of two energy development loans, totaling $300 million, for Argentina.

The votes broke a four-year tradition of voting no or abstaining on loans to countries considered human rights violators, one of the hallmarks of former president Jimmy Carter's foreign policy. They also added considerable fuel to the Washington debate over how the Reagan administration has mapped out a new world alignment of America's friends and enemies.

Both critics and supporters have acknowledged that the Argentina votes were devoid of almost any but symbolic meaning. The loans, like every other World Bank or Inter-American Development Bank loan granted to Argentina in recent years, would have been approved regardless of the U.S. vote.

But on an issue as weighty and emotinal, for both the Carter and Reagan administrations, as the U.S. commitment to human rights, it has been the symbolism that mattered.

In 1977, an act of Congress prohibited the United States from approving almost any World Bank or Inter-American Development Bank loan to countries exhibiting a "consistent pattern of gross violation of human rights." The act excepted only those loans aimed at "basic human needs." From then until the Argentina loan approval on July 7, American representatives abstained or voted no on all loans not involving "basic human needs" to the four nations of what is known as South America's southern cone -- Argentina, Chile, Paraguay and Uruguay.

With their governments either dominated or openly run by the military, a history of political repression throughout much of the 1970s, and a record of complaints of human rights violations that is unequalled in the West, the nations of the southern cone became the most visible targets of Carter's human rights campaign. Although there was never a blanket directive labeling the four countries "consistent and gross violaters," each loan application was studied by an interagency working group of U..s officials who assessed the human rights situation in the country in question. In every instance, during the Carter years, the situation was found to be so bad -- disappearances, political prisoners, torture, arbitrary detentions -- that U.S. approval was withheld.

When Secretary of State Alexander M. Haig Jr. two weeks ago defended the U.S. decision to approve all multinational development bank loans to the southern cone, he said one of the major reasons for the switch was the impressive changes he believed had taken place in the region.

"Without exception in each case the improvement has been dramatic," Haig said. "Now, that improvement does not represent ... a corresponding level of complacency here in Washington that all that must be done has been done. But we do not believe that it serves any useful purpose to indulge in isolation and public admonishment in the face of internal improvements that have already taken place."

Although there is no question that the governments of Argentina, Chile and Uruguay have almost completely stopped "disappearances," the most widely attacked repressive tactic of the 1970s, Haig's claim of "dramatic improvement" has met with skepticism here by the people who monitor human rights most closely. Country by country, here is a comparison between 1977 and 1981:

Argentina . By the end of 1977, the Buenos Aires-based Permanent Assembly for Human Rights had received testimony on the disappearance of 1,200 people.

The cumulative total -- people kidnaped or arrested who vanished without a trace -- today stands at about 5,800 in the assembly's records, although assembly members believe as many as twice that number may have disappeared without leaving relatives willing to report it.

In 1980, outside organizations such as Amnesty International reported to the assembly a total of 40 cases of disappearances but the assembly itself received only 18 reports. This year, according to assembly members, a western Argentina man who apparently had belonged to the Socialist Party was kidnaped and later found dead. Three other people were detained temporarily without any notice to their families, and two of them reportedly were tortured during their confinement. The assembly also received outside reports of the disappearance of two Chileans in southern Argentina last February, but was unable to confirm the reports.

In 1977, the assembly's records indicate that about 3,600 people were in jail under executive power, a special government dispensation that allows authorities to arrest and hold suspected political subversives or terrorists with or without formal charges. Last January, according to public statements by Interior Ministry spokesmen, 900 people remained under executive power, 300 of them without ever having been charged. Assembly members, who have similar figures on the number of people under executive power, say many of those who were charged have either completed their sentences or spent more than four years in prison with cases pending.

Political and labor activity is still illegal. Arrests and temporary detention of union and political leaders are routine, if somewhat haphazard. Rejecting internal pleas and strong international pressure -- much of it coming from the Carter administration -- the government has refused to release the names of the disappeared or make any accounting for the activity of security forces during the years when people were being taken from their homes and apparently killed in secret.

Chile . Of the approximately 700 disappearances reported to the Vicariate of Solidarity, the church-connected human rights organization generally viewed as the most reliable source of such information, only 14 took place in 1977. The last disappearance report the church received was in January 1978.

In 1977, following a massive release of political prisoners the year before, about 20 persons were in jail on what church records show as political charges. They now list 134 political prisoners -- not including those who have been charged with allegedly politically inspired violent crimes like bombings. In addition, during the first five months of 1981, 49 persons were sentenced -- under an administrative procedure for political charges that grants no due process -- to three months of internal banishment, meaning they were sent without money or provisions into small, isolated towns and told to fend for themselves and check in with the police on a regular basis.

During the first five months of 1977, 104 persons were detained on mostly nonviolent political charges, according to church records. During the same period in 1981, 578 persons were detained. The church has received 29 reports in 1981 from people who said they had been tortured by the Chilean secret police. As in Argentina, labor organizing and political activity are illegal, and show no signs of opening up in the near future.

Uruguay. In 1977, Amnesty International estimated that there were 5,000 political prisoners in Uruguay, and that 50,000 people had been detained at one time or another since the 1973 military coup, giving Uruguay the dubious distinction of having the most political prisoners per capita in the world.

The current number of what human rights groups refer to as "political prisoners" is estimated at between 1,100 and 1,500.The male prisoners are mostly housed at La Libertad, a prison that a late 1980 International Red Cross report strongly condemned for torturing and "bringing about the physical and moral breakdown" of its prisoners. Exile Uruguayan human rights groups have recently reported six mysterious prisoner deaths at La Libertad since last September. Each one was officially attributed to natural causes, but reports have persisted that the prisoners -- one of whom had been printing a newsletter inside the prison -- were harrassed or beaten to death.

Political activity has been illegal since 1973, and former political leaders are either exiled or officially banned from working in politics. But the atmosphere has loosened somewhat since voters in a national plebiscite soundly rejected a new constitution late last year.

Paraguay. In 1976, according to Washington-based experts on Paraguay, the country had 6,000 political prisoners, some of whom had been held as long as 19 years without trial. The number is now 30, and late last year Paraguay was taken off the United Nation's active list of countries most imperiling human rights. A general loosening of the political climate -- fewer press restrictions, more church activity in caring for prisoners and monitoring human rights -- drew praise for the Paraguayan government even from groups such as Amnesty International.

Paraguay has refused to allow the Organization of American States' Inter-American Commission on Human Rights to investigate conditions in the country, however. And within the past year human rights groups have grown alarmed about what the newsletter Paraguay Watch called "two major waves of repression" consisting of prolonged detentions, 15 deaths attributed to alleged abuses of human rights, and the recent arrest and expulsion of the chairman of the Christian Democratic Party. In addition, the government's sale of Indian-occupied lands has come under intense international criticism recently and been described in several studies as "genocide."

Whether any of this can be called a "dramatic improvement" has become a matter of heated debate -- particularly in the case of Chile, which still inspries bitterness in Washington because of the country's refusal to cooperate or extradite suspects in the 1976 Washington assassination of former Chilean diplomat Orlando Letelier and researcher Ronni Moffitt.

"Today, politically, it's not good to make somebody disappear," a Santiago human rights lawyer said last week."But as far as the new methods of repression -- torture, internal banishment -- I would say it's much worse than 1977."

To use the simple statistics "out of context, without telling the full story behind them, is a distortion of the facts," countered a State Department official familiar with Chile. Like many of those who believe the atmosphere has improved substantially in the southern cone, he said a certain tolerance -- undeclared breathing room for the opposition -- has replaced the full-scale terror of the mid-1970s: "It is the threat of killing and disappearances that really stamps that out."

In Buenos Aires, a middle-aged woman who still does not know whether her son is alive or dead set down her pages of human rights data and slowly shook her pages of human rights data and slowly shook her head. "What I'd say to Senor Haig, if he wanted to hear me, is that the whole structure permitting the kidnapings, permitting the tortures, the arrests -- the whole structure has been left intact," she said. "If they want to start again with the whole business, they can. And this remains like a terror over all of us. Be careful with this policy, Senor Haig. That is what I would say to him."