You had to know this was going to happen.  CREW did.

Just over a year ago, in the wake of a decision by the U.S. Court of Appeals in the case against William Jefferson, which found that the Constitution's Speech and Debate clause prohibits searches of congressional offices by the executive branch, Melanie Sloan predicted this would become an issue in the case against Senator Ted Stevens:

Nevertheless, this ruling may have a profound impact on the government's ability to thoroughly investigate other cases of congressional corruption. For example, Sen. Ted Stevens (R-AK) now has every incentive to store in his congressional office any document concerning the renovations of his house, secure in the knowledge that it will be beyond the reach of federal investigators.

In fact, that has come to pass. Stevens is now using the speech and defense clause as a defense in his criminal tria to prevent the testimony of his staffers:

Sen. Ted Stevens accused the Justice Department of trampling on the independence of Congress, arguing Thursday that the corruption case against him should be thrown out.

That legal argument will test the limits of a court ruling that prosecutors fear could limit their ability to investigate corruption on Capitol Hill. Stevens said FBI agents went too far when they questioned his Senate aides.

The Alaska Republican is scheduled to go on trial next month on charges that he lied on Senate disclosure records about hundreds of thousands of dollars in gifts and services he received from a powerful oil services contractor, Veco Corp.

Stevens said the FBI's long-running corruption probe intruded on his Senate affairs. He cited the Constitution's speech-or-debate clause, which prohibits the executive branch from using its law enforcement authority to interfere with legislative business.

This could actually slow down the proceedings that Stevens was hoping to expedite so it could wrap up before Election Day.