Legal analysts locate those protections in Article I, Section 6 of the Constitution, known as the "Speech or Debate" clause, intended to ensure that Congress was not intimidated or controlled by the executive branch. Typically, when there's a subpoena for congressional documents, it goes to the House or Senate legal counsel to make certain that congressional interests are being protected. Otherwise, there's no protection for the executive branch rifling through committee papers, for example.
The Justice Department appeared aware of the potential problem. In a statement on Monday, Attorney General Alberto Gonzales said the FBI had used special procedures to deal with constitutionally protected materials. "I think the executive branch intends to work with the Congress to allay those concerns."
Reportedly, those procedures included the use of a "filter team" to determine whether any of the seized documents were privileged. The team, made up of FBI agents and prosecutors who were independent of the investigation, would keep such documents from being perused. A judge was to rule on any seized documents whose status was in question, according to the affidavit.
A federal district judge in suburban Virginia issued the warrant that allowed the FBI to search Jefferson's office.
"It's an extremely complex area of constitutional law," says Carl Tobias, a law professor at the University of Richmond. "Historically, even if the FBI had a warrant, there's no precedent for intrusion into the office of a member of Congress."
But with the approval rating for Congress at 21 percent - three points short of its all-time low - there are signs that the public isn't picking up such constitutional distinctions. Nearly half of Americans believe that most in Congress are corrupt and that corruption affects both parties equally, although they trust Democrats to handle the issue better than Republicans, according to a recent Gallup poll.
"The tone has been set by the top of the Republican Party. I've never seen a Congress as corrupt as I've seen here, and I've been in the Congress 32 years," said Rep. Henry Waxman (D) of California.