The U.S. Supreme Court case Long v. Ansell in 1934 revolved around the issue of whether a member of Congress could be sued for libel during congressional recesses, based on statements made while Congress was in session. The plaintiff, Huey P. Long, a senator from Louisiana, had been sued by William H. Ansell for defamation due to comments made on the Senate floor that were later published and distributed throughout his home state during a recess period. The court ruled in favor of Senator Long stating that members of Congress are immune from lawsuits related to their legislative activities under Article I Section 6 Clause 1 (the Speech or Debate Clause) of the Constitution - even when those actions occur outside an active Congressional session or involve dissemination beyond Congressional precincts. This ruling reinforced the principle that lawmakers should have broad immunity from legal repercussions tied directly to their legislative duties so as not to impede them in carrying out these responsibilities effectively.

In the dissenting opinion for Long v. Ansell, Justice McReynolds disagreed with the majority's interpretation of Article I, Section 6 of the Constitution which provides immunity to members of Congress from arrest during their attendance at sessions and in going to or returning from them. He argued that this privilege was intended by framers to protect legislators from being hindered in performing their duties due to arrests on civil process, not as a shield against personal responsibility for individual debts. The justice believed that Congressman Long should be held accountable for his debt despite his congressional status and session schedule. He also pointed out that there were no historical instances where such an expansive interpretation had been applied before this case.