WASHINGTON - A special federal appeals court ruled yesterday that the Justice Department had broad new powers under the anti-terrorism bill enacted last year to use wiretaps obtained for intelligence operations to prosecute terrorists.

The immediate effect of the ruling by the three-member panel is that criminal prosecutors may take an active role in deciding how to use wiretaps obtained from a special intelligence court and should have greater access to information obtained from those surveillance operations. For more than 20 years, prosecutors have been prohibited from directing the applications for intelligence wiretaps because the standards of proof are widely believed to be lower than for regular criminal wiretaps.

But the judges said yesterday that passage of the legislation, known as the USA Patriot Act, ensured that there was no wall between officials from the intelligence and criminal arms of the Justice Department. In fact, the judges asserted that the 20-year-old practice of keeping the two groups of officials largely separate was never required and was never intended by Congress.

"Effective counterintelligence, as we have learned, requires the wholehearted cooperation of all the government's personnel who can be brought to the task," the appeals court wrote. "A standard which punishes such cooperation could well be thought dangerous to national security."

The opinion was a significant victory for Attorney General John Ashcroft, who announced immediately that he would use it to greatly expand the use of the special intelligence court by prosecutors to obtain wiretaps of people suspected of involvement with terrorists.

"This is a giant step forward," Ashcroft said at the Justice Department, adding that he would swiftly increase the number of lawyers at the FBI and in prosecutors' offices around the country to seek authorization for new wiretaps and surveillance orders to combat terrorism.

"This revolutionizes our ability to investigate terrorists and prosecute terrorist acts," he said.

The ruling also adds momentum to the Bush administration's determination to shake off restrictions on how investigators have operated since the Sept. 11 attacks, including the lifting of restrictions on investigators using the Internet to compile databases to be used to combat terrorists. It may also oblige the FBI to share information gathered by its counterintelligence agents more readily.

Both the appeals court and the court whose opinion it overturned yesterday were created to administer a 1978 law allowing the government to conduct intelligence wiretaps inside the United States. The three-member appeals court, called the U.S. Foreign Intelligence Surveillance Court of Review, in issuing its first opinion ever, said that the lower court, the Foreign Intelligence Surveillance Act court, had erred when it tried to impose restrictions on the Justice Department.

Appeal unclear

Because of the unusual nature of the law on which the case was decided, it was unclear whether anybody is in a position to appeal yesterday's ruling to the Supreme Court. The only party in the case was the Justice Department, which won; the American Civil Liberties Union and the National Association of Criminal Defense Lawyers, who filed briefs, were afforded only friend-of-the-court status, which does not entitle them to bring an appeal.

Ann Beeson, litigation director of the ACLU's Technology and Liberty Program, said her group was exploring whether there is any way that it can challenge the new authority.

The case arose in May when the lower court, which decides whether to grant intelligence authorizations, ruled on an application submitted by Ashcroft's investigators. At the time, the court ordered the government to meet certain conditions to obtain authorization to wiretap an individual who is identified in court papers only as a resident of the United States who is working as an agent of a foreign power.

The three members of the lower court ordered the Justice Department to show that the primary purpose of the application was for intelligence gathering and not really for a criminal case. Moreover, the court ordered that prosecutors in the Justice Department's Criminal Division could not take an active role in directing the activities of the intelligence division.

The notion of a separation arose first in the 1980s and was put into Justice Department regulations in 1995. The reason was that the requirements for obtaining a wiretap for intelligence gathering were thought to be easier to meet than those for a straightforward criminal investigation. As a result, investigators were instructed not to try to avoid the stricter standards for a criminal investigation by pretending it was for intelligence gathering.

Debate exposed

Although the world of national security wiretaps has always been conducted out of public view, Ashcroft's challenge of the lower court ruling exposed the debate in the government over the balance between civil liberties and national security that heated up after the Sept. 11 attacks.

In an unsigned opinion, the appeals court judges unanimously ruled that Ashcroft was correct in saying that the USA Patriot Act swept away the distinctions between the intelligence and criminal sides of the government's national security operations. Even more striking in the court's ruling was the strong assertion that the restriction that had been observed for two decades before the passage of the new law was never required.

The appeals court also asserted that the requirements for obtaining wiretap authorization under the intelligence law were not that different in a constitutional sense from the requirements for obtaining a warrant in a criminal case, challenging a widely held assumption.

The foreign surveillance court and the court of review were established under a 1978 law that was intended to impose a formal court process on the approval of wiretaps in national-security investigations. In its 24-year history, the lower court had never rejected a request from the Justice Department although lawyers said that some applications were sent back for modification.

The Foreign Intelligence Surveillance Court of Review, which had never met before this case and essentially existed on paper, is made up of Judges Ralph B. Guy of the 6th U.S. Circuit Court of Appeals, Edward Leavy of the 9th U.S. Circuit Court of Appeals and Laurence H. Silberman of the District of Columbia U.S. Circuit Court of Appeals.