A federal court on Wednesday ruled that an abortion law signed by President Bush last year was unconstitutional and banned the U.S. Justice Department from enforcing it, joining two other states that struck down the law.

In a 476-page opinion and judgment, U.S. District Judge Richard Kopf said the Partial-Birth Abortion Ban Act of 2003, was “unreasonable and not supported by substantial evidence.” He agreed with critics who claim the types of abortion banned in the law are sometimes necessary to protect a woman’s health.

Last month, a federal judge in New York also ruled against the government’s ban. And in June, a San Francisco judge also barred the U.S. Justice Department from enforcing the ban.

“It is a clean sweep, the third decision to strike down this law,” said Priscilla Smith, attorney for the Center for Reproductive Rights, which helped challenge the law.

“The judge issued a painstakingly detailed almost 500-page opinion. That really should put this issue to rest once and for all,” Smith said.

The Justice Department issued a statement declaring that it “will continue to defend the law to protect innocent new life from partial birth abortion,” and noted that Attorney General John Ashcroft has already appealed the San Francisco case.

Bush has said the law, signed last November, affirms “a basic standard of humanity, the duty of the strong to protect the weak.”

But opponents of the ban say it not only outlaws a procedure sometimes necessary to protect the mother’s health, but it is so vaguely worded that it would outlaw other common abortion methods.

Supporters of the ban say it is a narrowly written law that bans only a specific procedure that is never medically necessary.

The procedure in question is often called “partial-birth” abortion because it may involve partially removing a fetus from the womb to terminate it. Doctors convicted of performing the procedure could be imprisoned for two years under the 2003 Act.

But Kopf’s ruling, which is more than double the length of either of the two previous rulings, concluded that Congress’ findings that dilation and extraction abortions were never warranted were “factually unsound.”

The judge said that testimony from numerous witnesses, including the Justice Department’s own medical experts, offered examples of cases in which dilation and extraction was needed for women who were hemorrhaging, suffering from cancer of the placenta, or experiencing other medical complications.

The law is unconstitutional because “it does not allow, and instead prohibits, the use of the procedure when necessary to preserve the health of a woman,” Kopf stated in his ruling.

Kopf said his ruling applied only to abortions involving a fetus that was not viable outside the womb. He did not take a stand on whether the law was constitutional for abortions involving fetuses that would be “indisputably viable.”