U.S. District Court Judge Gladys Kessler said that while the political and policy issues surrounding the case were complex, "the legal issue, in contrast, is simple and straightforward."
President Bush has said the Navy should abondon its training on Vieques no later than May 2003. Many in Puerto Rico, however, fear that the U.S. war in Afghanistan will cause him to back away from the pledge.
Puerto Rico filed its lawsuit last April after Gov. Sila Calderon signed a law banning loud noises along the island's shores. That law cited the U.S. Noise Control Act of 1972, which allows states or, as in Puerto Rico's case, U.S. territories to set noise-control laws.
The United States has used Vieques, a 33,000-acre island off eastern Puerto Rico, as a bombing range for more than 50 years, but it has faced increasingly vociferous protests by Puerto Ricans and environmentalists.
In a ruling issued Monday and released Wednesday, Kessler said she must dismiss Puerto Rico's case "for lack of subject matter jurisdiction." She said the Noise Control Act "does not provide plaintiff a cause of action to sue in federal district court for the violations alleged."
Puerto Rican Justice Secretary Anabelle Rodriguez pledged to appeal.
"We think the decision is erroneous," she said at a news conference Wednesday in San Juan, Puerto Rico.
"It's sad," said Nellie Rodriguez, wife of the Vieques mayor, Damaso Serrano. "We'll have to keep fighting another way; for example, by putting a lot of pressure on the president."
Despite Mr. Bush's pledge to eventually end naval training on Vieques, Congress passed legislation last month to bar the Navy secretary from closing the site until he and top military leaders certify the availability of a site or sites that would provide "equivalent or superior" levels of training.
A Pentagon spokesman would not comment Wednesday because he had not seen the ruling.
Dana Perino, a Justice Department spokeswoman, said government attorneys were analyzing the ruling but were pleased with the decision.
Puerto Rican researchers have linked heart disease and other health problems found among Vieques residents to naval gunfire and pollutants released during military exercises.
The Navy denies the allegations.
Opposition to the Navy's use of Vieques intensified after a jet dropped two errant bombs in 1999 that killed a civilian Puerto Rican guard.
The Navy owns about half of Vieques, and the bombing range covers 900 acres on the island's eastern tip.
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