Hutchinson v. Proxmire
United States Supreme Court
443 U.S. 111 (1979)
Senator Proxmire (defendant) gave behavioral scientist Hutchinson's (plaintiff) federal research sponsors a "Golden Fleece" award mocking their funding as wasteful, then publicized his views through 100,000 mailed newsletters, a press release, TV and radio appearances, phone calls, and remarks on the Senate floor; Hutchinson sued for defamation. The court of appeals held the Speech or Debate Clause protected the newsletters and press release, and that the First Amendment separately protected the phone calls and broadcast appearances.
Whether the Speech or Debate Clause protects a member of Congress's newsletters, press releases, and other public communications repeating defamatory remarks, when those communications occur outside the actual legislative chamber and aren't essential to the legislative deliberation process.