In Hutchinson v. Proxmire et al., the U.S. Supreme Court ruled that members of Congress are not protected by the Speech or Debate Clause for defamatory statements made outside of formal congressional proceedings. The case arose when Senator William Proxmire awarded his satirical "Golden Fleece Award" to Dr. Ronald Hutchinson, a behavioral scientist whose research was federally funded, implying that his work was wasteful and frivolous. Dr.Hutchinson sued for defamation and won in lower courts; however, Senator Proxmire argued he should be immune from such suits due to the Speech or Debate Clause which protects legislative actions within Congress from being questioned in any other place. The Supreme Court disagreed with this argument stating that while speeches given on the Senate floor were protected under this clause, press releases and newsletters were not part of 'legislative action' hence they did not enjoy immunity protection under it.

In the dissenting opinion for Hutchinson v. Proxmire et al., Justice William Brennan, joined by Justices Byron White and Thurgood Marshall, argued that the majority's decision to not extend absolute immunity to members of Congress for their statements made outside of formal legislative proceedings was a misinterpretation of the Speech or Debate Clause. The dissenters believed that this clause should protect legislators from being held liable for defamatory remarks made in connection with their legislative duties, regardless of where they were uttered. They contended that such protection is necessary to ensure lawmakers can perform their roles without fear of legal repercussions stemming from public criticism or controversy. Furthermore, they expressed concern about potential chilling effects on free speech and democratic debate if politicians had to constantly worry about possible defamation suits related to their comments on public issues.