A third federal judge has ruled the Partial-Birth Abortion Ban Act unconstitutional, adding judicial weight that some experts say could keep the issue from reaching the U.S. Supreme Court.

U.S. District Judge Richard Kopf of Lincoln ruled against the measure Wednesday, saying Congress ignored the most experienced doctors when it determined that the banned procedure would never be necessary to protect the health of the mother -- a finding he called "unreasonable."

His ruling echoed decisions by federal judges in New York and San Francisco. The abortion ban was signed last year by President Bush but was not enforced because the three judges agreed to hear constitutional challenges in simultaneous non-jury trials.

The ban, which President Bill Clinton twice had vetoed, was seen by abortion rights activists as a fundamental departure from the Supreme Court's 1973 precedent in Roe v. Wade. But the Bush administration has argued that procedure, called "partial-birth" abortion by its opponents, is cruel and unnecessary and causes pain to the fetus.

If each judge is upheld by federal appeals courts, the high court might not take up the issue, said Priscilla Smith, a lawyer with the New York-based Center for Reproductive Rights.

"If all the appellate courts uphold those decisions, there is no reason for it to go to the Supreme Court," Smith said.

Not everyone agreed.

"It's very unusual for the court not to take a case where an act of Congress has been struck down," said Jay Sekulow, chief counsel for the American Center for Law and Justice, which supports the ban. "I would be very surprised if the court took a pass on this."

The Nebraska lawsuit was filed by the Center for Reproductive Rights on behalf of physicians including LeRoy Carhart, who also brought the challenge that led the high court in 2000 to overturn a similar ban passed by Nebraska lawmakers.

"The Supreme Court already said what the law is four years ago," Smith said. "The judges all across the country, from different political persuasions, applied the law and uniformly found it unconstitutional."

Louise Melling, director of the American Civil Liberties Union's Reproductive Freedom Project, agreed with Smith. "What you have is a decision of a mere four years ago striking a similar ban," she said. "And now you have three courts striking a ban for the same reason."