Arias adviser pays price for politics. Under heat from US critics, he quits job and Costa Rica

After boosting Oscar Arias S'anchez to power and helping draft the historic Central American peace plan last year, John Biehl might have expected a hero's welcome in Costa Rica. But instead, the affable Chilean adviser - President Arias's closest friend and confidant - has been hounded out of the country by conservative critics both here and in the United States, Costa Rican officials and foreign diplomats say.

Before heading to his homeland, Mr. Biehl joined his Costa Rican supporters for a last public event yesterday, at the inauguration of Ecuadorean President Rodrigo Borja. The departure of Mr. Arias's ``alter ego'' is especially hard for the Nobel Peace Prize-winning President at a time when their year-old peace initiative is threatening to fade into irrelevance.

Ever since early 1987, when Arias and his kitchen cabinet first forged the plan that would eventually foil the Reagan administration policy of funding the Nicaraguan contra rebels, Biehl has become a target for angry US conservatives, his supporters say.

While working for the UN Development Program, Biehl was ``very instrumental in getting Oscar elected and helping devise the peace plan,'' says a fellow adviser. ``But he has developed some real enemies in the [US] administration.''

According to supporters, the campaign against Biehl officially began with a June 1987 letter. Robert Kasten Jr. of Wisconsin - the ranking Republican on the Foreign Operations Subcommittee of the Senate Appropriations Committee - wrote to the UN Development Program complaining that UN employees like Biehl should not have the power to lobby and advise governments. Senator Kasten suggested that Biehl's continued employment might force a withdrawal of crucial US contributions. A Costa Rican newspaper's publication of the letter, and the ensuing uproar, soon forced Biehl to quit the UN program.

During the following year, some US officials continued pushing Arias to dismiss his longtime adviser, a Costa Rican official says. But the criticism really got hot in late May of this year, when Biehl blasted the US's Central American policy in an interview with a Chilean magazine. US officials complained that Biehl, who played the role of a diplomat, shouldn't be free from accountability just because he was Chilean.

Outraged right-wing groups here, especially annoyed by Biehl's charges that the US is trying to create a ``parallel state'' in Costa Rica, called for Biehl's deportation.

Arias refused. The two had become friends and intellectual partners over 20 years ago, when both were studying political science at the University of Essex in England. Biehl, a balding man with wild locks of hair flying over his ears, still has the air of the burly professor who taught at the University of Liverpool in the early '70s. In 1975, Biehl left for a UN job in Costa Rica.

Despite the support of Arias and other officials, Biehl announced his departure a few weeks after the interview was published.

US officials deny involvement in his decline. ``John Biehl did it to himself,'' says a senior US official, referring to the damaging interview. ``He's an extrovert, likes to talk, a fabulous guy, great sense of humor. He made a mistake.''

Biehl, on one of his last afternoons here, said his family had decided to leave before the interview was published. But there is no denying his intense contempt for current US-Latin American policy.

``It's like a hippopotamus playing the piano,'' Biehl says. ``All the notes sound at once.''

Like Arias, he says that the US's indelicate use of the Nicaraguan rebels endangers the plan that promotes peace and democratic freedom in Central America without using the discordant note of military force.

A month after the Nicaraguan government cracked down on the opposition, Biehl says the balance of world opinion has swung sharply against Nicaragua. European allies are drawing back. US Democrats are reevaluating their positions. And Arias is trying to mount Latin American pressure on Nicaragua to create democratic openings.

Were it not for continued US backing of the contras, Biehl says, the desperately poor Nicaraguan government might soon be forced to soften its internal policy and return to the negotiating table.

``As soon as you have Shultz trying to say that the contras are back, you upset that balance. You need a cooler policy with more sophistication,'' he says.

When he returns to Chile, Biehl plans to write a book about US policies toward Latin America. Despite his role in creating a Latin-initiated peace plan - and despite his strong streak of anti-Americanism - the pact's general failure has shown him the narrow limits of truly independent action in Latin America.