The Justice Department is appealing a federal court ruling that found the 2005 search of Rep. William Jefferson’s (D-La.) Capitol Hill office unconstitutional, arguing that the court’s logic may make it impossible to execute a search warrant on a Member of Congress anywhere.

The U.S. Court of Appeals for the District of Columbia ruled in August that even though the FBI was seeking non-legislative documents, the search of Jefferson’s Rayburn office violated the Speech or Debate Clause of the Constitution because agents of the executive branch seized and reviewed material in his office without first allowing the Congressman to assert his privilege over those materials that are “legislative” in nature.

Jefferson has been charged with accepting bribes in exchange for helping a company win contracts in Africa, charges the Congressman denies.

In a brief filed this week, the Justice Department is seeking an “en banc” rehearing of the August ruling, arguing that the court may have handicapped future criminal proceedings by essentially ruling that executive agents may not even see legislative materials, even if the materials are not being used to prosecute a Member of Congress.

“This unprecedented expansion of the Clause has not only delayed the instant investigation by requiring ex parte adjudication of Rep. Jefferson’s privilege claims,” the government wrote, “it also threatens to complicate numerous ongoing and future investigations by inviting litigation over routine techniques employed by federal agents.”

Since the ruling appears to apply anywhere that agents are likely to encounter legislative materials, the limits on searches without prior notice “may reach beyond Capitol Hill to searches of a Member’s car, briefcase or home-state office,” Justice Department lawyers wrote.

The Justice Department brief also suggests that other Members already are using the Jefferson case as a shield against investigations: “The underlying principle of the case has been interpreted by some Members to preclude agents from conducting voluntary interviews with Hill staffers without the Members’ consent.”

If allowed to stand, the court’s ruling would cede control of the search location to the target of the search — the Member of Congress — instead of the investigating agents, creating opportunities for the Member to rearrange or obscure important evidence, the Justice appeal argues.