An Argentine intellectual related a recent conversation with a Chilean friend.

"We got into the rather ghoulish question of whose government is more repressive," he said. "Which country deserves a worse international reputation."

The answer, the Argentine said, was that, while repression by military governments in both countries is severe, it is perhaps less terrfying in Chile because "at least in Chile, there are some rules to the game. One knows how far one can go."

The notion of "rules" to the "game" is a very real concept to those living under the military regimes of these two South American nations. They are the guidelines for daily activity, the boundaries of dissent and the unstated but definite penalties for overstepping those bounds.

While the distinctions may appear unnecessarily fine to the American mind, there are definite differences between the two South American dictatorships.

These differences have worked to the advantage of Argentina, and the disadvantage of Chile, in terms of overseas image. Although both countries' records on human rights are sullied, Chile's image in the rest of the world is far worse than Argentina's.

One of the main reason is that Chile provides a much clearer target for criticism. The military junta has had four years to consolidate its power. While factionalism exists among and within branches of the armed forces in both countries, it is much less pronounced in Chile.

"They may argue privately among themselves," said one Chilean civilian official, "but when the chips are down, there is no question of total support for Pinochet."

Gen. Augusto Pinochet, chosen by the junta as president, is a dictator in the traditional mold. According to both friends and enemies, his power is almost absolute.

That power, and a Chilean tendency toward legalism and respect for authority, has created a well-defined system of repression. Newspapers and magazines are subject to censorship, political parties are outlawed, and labor unions are governored by strict rules.

By the same token, Pinochet's establishment of a powerful state security agency insured that the finger of guilt would be accurately pointed when politically active Chileans disappeared.

Eighteen months after seizing power, Argentine President Gen. Jorge Rafael Videla wields no such obvious power. Rumors of his imminent overthrow by hardliners within the government circulate periodically and his aides enthusiastically report them as evidence that he is trying, against difficult odds, to be a moderate.

Argentina has no well-defined security police network. Rather, each branch of the armed forces maintains its own intelligence agency and countless unofficial subgroups answerable to widely diffused lines of military authority.

Argentina has few press cencorship laws, relying instead on a system of "self-censorship" that effectively cows most publishers.

Political parties and labor unions are merely "suspended" in Argentina, with only vague definitions of what activities they can still carry out.

Estimates of the number of Argentines who have disappeared since the junta assumed power range from 5,000 to 20,000. While the government privately admits having at least 4,000 persons under detention, it has no explanation for the disappearance of a numbe of prominent Argentines, many ostensibly allied with the Videla faction. They presumably have been snatched on orders form his enemies within the military.

As a result of such confusion of authority, foreign journalists often find it difficult to pinpoint the blame for abuse of human rights in Argentina and are left reporting the "difficult" situation here.

No such kid gloves are applied to Pinochet, whose highly structured police agency, DINA, recently renamed, was blamed with some certainty for abducting more than 700 chileans - by conservative estimate.

There is evidence that the Argentine junta is not quite as disorganized as it appears, and informed sources say that the Argentine military carefully studied the Chilean model before making its move last year.

Its conclusion, sources say, was that if it were to impose a rigid structure complete with repressive decrees and carefully justified legalisms, it would end up with the same bad image as the Chileans.

Just as there are differences between the junta, opposition movements within the two countries also are different.

In Chile, where there is a long tradition of strong political parties and elected civilian government, most of the parties are uniformly horrified at what has occurred. They have buried their disagreements and joined in an increasingly powerful and effective opposition.

Human-rights groups actively coordinate efforts under the auspices of the Roman Catholic church.

Argentina's political parties have been in disarray for the past 60 years, during which there has been a total of 23 different presidents, 12 civilian and 11 military, whose terms ranged from three days to nine years.

The human-rights movement in Argentina is spread thinly over a number of groups. They have little contact with each other and bombard journalists and sympathizers with a stream of widely differing lists of disappearances and atrocities.

The same problems are reflected overseas, where the well-organized Chilean exiles receive considerable publicity, while Argentine exiles generally carry their domestic quarrels along with them.

On recent visits to both Chile and Argentina, Assistant Secretary of State for Latin America Terence Todman noted that "the information we receive outside the country does not always correspond to the reality" here.

While foreign journalists and exiles took the remarks as a criticism of their activities, many admit that the "rules of the game" often impede a fair assessment of the situation.