In a precedent-setting opinion that contradicts a long-held Immigration and Naturalization Service position on political asylum, the Ninth U.S. Circuit Court of Appeals has ruled that a Salvadoran immigrant's neutrality in his country's civil war constitutes a "political opinion" and is therefore a valid basis for asylum.

The court also ruled that the immigrant's claim for asylum does not require independent corroboration, since refugees fleeing violence-wracked nations rarely have the opportunity to bring evidence of persecution with them.

Immigration lawyers hailed the unanimous ruling by a three-judge panel as a significant change that may lead to a marked increase in grants of asylum to immigrants from war-ravaged countries.

The lawyers viewed the decision, which was released here, as particularly important for Salvadorans because many of them are believed to have fled violence from various factions in their country's civil war.

"It establishes for the first time that a political-asylum applicant need not be a partisan on either side of a civil war in order to obtain refugee status," said Peter Schey, director for the National Center for Immigrants' Rights Inc.

The ruling also is believed to be the first to address directly the issue of whether corroborative evidence of a petitioner's testimony is required in a claim for asylum.

Contending that "authentic refugees rarely are able to offer direct corroboration of specific threats," the panel reversed a decision by an immigration judge and ruled that no independent corroboration is required.

INS officials said that they might appeal the ruling.

"All it does is open up a Pandora's box," said William Odencrantz, regional counsel for the INS western region office. "An area that looked somewhat settled now looks unsettled." He added that the ruling's "ultimate effect" can only be determined over time, as the decision is applied in other cases.

The ruling was handed down on an appeal by Espectacion Bolanos Hernandez, who sought political asylum after entering the United States illegally in 1982. Bolanos said he had participated in a right-wing political party in El Salvador and had been a member of a voluntary civilian police squad. He said he fled the country when a guerrilla group threatened to kill him if he did not join them.