WASHINGTON (AP) – An FBI raid on a Louisiana congressman’s Capitol Hill office was legal, a federal judge ruled Monday.

Chief U.S. District Judge Thomas F. Hogan said members of Congress are not above the law. He rejected requests from lawmakers and Democratic Rep. William Jefferson to return material seized by the FBI in a May 20-21 search of Jefferson’s office.

In a 28-page opinion, Hogan dismissed arguments that the first-ever raid on a congressman’s office violated the Constitution’s protections against intimidation of elected officials.

“Congress’ capacity to function effectively is not threatened by permitting congressional offices to be searched pursuant to validly issued search warrants,” said Hogan, who had approved the FBI’s request to conduct the overnight search of Jefferson’s office.

Jefferson had sought the return of several computer hard drives, floppy disks and two boxes of paper documents that FBI agents seized during an 18-hour search of his Rayburn Building office.

At issue was a constitutional provision known as the speech and debate clause, which protects elected officials from being questioned by the president, a prosecutor or a plaintiff in a lawsuit about their legislative work.

“No one argues that the warrant executed upon Congressman Jefferson’s office was not properly administered,” Hogan wrote. “Therefore, there was no impermissible intrusion on the Legislature. The fact that some privileged material was incidentally captured by the search does not constitute an unlawful intrusion.”

The raid on Jefferson’s office angered members of Congress, some of whom threatened to retaliate by tinkering with the FBI and Justice Department budgets.

President Bush stepped in and ordered the solicitor general to take custody of the seized materials so Congress and the Justice Department could work out procedures to deal with similar situations in the future.

The president’s 45-day “cooling off period” ended Sunday with no compromise worked out but with assurances from the Justice Department that it would not seek to regain custody of the materials until Hogan ruled on Jefferson’s request.

Because Hogan signed the search warrant authorizing the search, Jefferson’s legal team was not surprised by his ruling upholding it.

“While a Congressman is not above the law, the executive branch must also follow the law,” said Jefferson’s lawyer, Robert Trout. “We appreciate the consideration the judge accorded our motion for the return of the seized property, but we respectfully disagree with his conclusion, and we intend to appeal the ruling.”

Hogan said a search warrant seeking material is very different than a subpoena seeking testimony.

“Jefferson may never be questioned regarding his legitimate legislative activities, is immune from civil or criminal liability for those activities, and no privileged material may ever be used against him in court,” the judge wrote.

Jefferson has been under investigation since March 2005 for allegedly using his position to promote the sale of telecommunications equipment and services offered by iGate, a Louisville-based firm, that sought contracts with Nigeria, Ghana and other African nations.

In return for his help, Jefferson allegedly demanded stock and cash payments. Jefferson has not been charged and has denied wrongdoing.