A federal judge yesterday struck down as unconstitutional a Guam law prohibiting virtually all abortions. The measure was the nation's most restrictive abortion law.

U.S. District Judge Alex Munson declared that Roe v. Wade, the 1973 Supreme Court decision that legalized most abortions, "applied with equal force and effect to Guam."

The law, signed by Gov. Joseph Ada (R) March 19, banned abortions except to protect the woman's life. It had been unanimously approved by the Guam legislature despite an opinion from Guam's attorney general that it is unconstitutional. On March 23, Munson blocked its enforcement while he considered a challenge to the law by abortion rights advocates.

Guam's law makes it a felony to perform an abortion, punishable by as much as five years in prison. The law carries a misdemeanor penalty of as much as a year in jail and a $1,000 fine for obtaining an abortion or soliciting a woman to have an abortion.

The governor said he had not decided whether to appeal yesterday's ruling. "I'm still very pro-life, and I believe that a fetus is a human being and should be given life," said Ada, a Roman Catholic like the vast majority of Guam residents. He has 30 days to decide whether to appeal.

The Guam measure is the only case left this year that could provide a vehicle for antiabortion forces to challenge Roe v. Wade. Similiar measures were vetoed earlier by the governors of Idaho and Louisiana.

Anita Arriola, a lawyer for the abortion rights side, had argued that the law was contrary to Roe v. Wade, that it violated numerous constitutional guarantees, including the explicit guarantee of liberty, and was enacted to promote a particular religious belief.

In reply, lawyers for the government of Guam, an unincorporated U.S. territory in the Western Pacific, had argued that 99 percent of abortions on Guam were not necessary but were for convenience. The government also argued abortion is inconsistent with Guam's "indigenous cultural tradition," calling Catholism a territorial tradition.

In his ruling, Munson said sections of the law are vague and that the provision against soliciting an abortion violated the right to free speech. He also questioned the religious motivation of the statute.

"We figured that it wouldn't be an easy climb," Roland Rivera, vice president of Guamanians United for Life, told the Associated Press. "There is just the next higher level to pursue."

Lynn Paltrow, an American Civil Liberties Union lawyer who served as co-counselor in the challenge to the Guam law, said that among the factors Ada must consider in deciding whether to appeal is "the exhorbitant cost to Guam taxpayers of continuing the legal fight."