In Gravel v. United States (1971), the U.S Supreme Court ruled that the protections of the Speech or Debate Clause in Article I, Section 6 of the Constitution extended to Congressional aides, but not to activity outside the legislative process. The case arose when Senator Mike Gravel received a copy of classified Pentagon Papers and arranged for their publication by Beacon Press. He also read portions into his subcommittee's record during a late-night session without other members present. When investigations were initiated against him and his aide Leonard Rodberg who had assisted with these actions, they claimed immunity under the Speech or Debate Clause which protects Senators from being questioned about their legislative acts in any place except Congress itself. The court held that while this clause did protect them from prosecution for reading papers into Senate records as part of official proceedings, it didn't extend to arranging third-party publication since this was not an integral part of law-making process.

In the dissenting opinion for Gravel v. United States, Justice Harlan argued that Senatorial privilege should not extend to aides or staff members of a senator. He believed that the Speech and Debate Clause in Article I of the Constitution only protects Senators and Representatives themselves, not their employees. Furthermore, he contended that extending this protection to staffers could potentially lead to abuses of power as it would allow senators to shield any illegal activities simply by having their aides perform them on their behalf. This interpretation was based on his belief in maintaining checks and balances within government institutions; if lawmakers were able to circumvent legal consequences through such means, it would disrupt these necessary boundaries between branches of government.