For a good look at one game of international politics, you should have been at Meridian House last night where the Council of the Americas was having a dinner for Jose Napoleon Duarte, the president of El Salvador.

Of course, you couldn't have walked up the red-carpeted stairway to the reception, past government agents with earphones, unless your name was on a list. And you couldn't have gone to the dinner behind huge double doors unless you were one of a select crowd of 40 or so.

You couldn't even get a guest list if you wanted just to look. "This is a private dinner," said Carmen Sarmiento, who has a private consulting business and helped out with the dinner.

Not exactly a typical Washington mob-scene fund-raiser. But a fund-raiser of a subtle sort. Although Duarte, taking his seat at the dinner, said he didn't quite see it that way. "I did not come here to ask for any economic aid," said the president of the civil-war-torn country. "My duty is to express our willingness to look for a solution and the understanding of the people of the United States." Duarte, who is here on a private visit, had said Sunday that he is seeking $300 million in economic aid from the international community.

Duarte described his trip here so far as "very good. I've had the opportunities I was hoping for. I've been on three television programs . . . I've talked to many people."

At one point during the reception he spoke with a sober-faced huddle that included the president of the Inter-American Development Bank, the Salvadoran representative to the bank and an official of the World Bank.

"He's seeking money where it counts," commented one seasoned observer.

Among the guests were Deane Hinton, the U.S. ambassador to El Salvador; a variety of officials from the Council of the Americas and about 20 of its members; Joseph J. Jova, the president of Meridian House International and a former ambassador to Mexico; and William Doherty of the AFL-CIO.

"We're for freedom and democracy and land reform," said Doherty as he found his seat at dinner. Two American land-reform experts working for the AFL-CIO were killed in El Salvador in January.

The Council of the Americas is an association of U.S. private businesses with concerns in Latin America. It includes about 200 of the 500 largest corporations in America, according to Sarmiento.