On July 7, 1797, the House of Representatives informed the Senate of its determination to present articles of impeachment against Senator William Blount (pictured), a Tennessee Federalist. The House based its decision on evidence provided by President John Adams that Blount had conspired to seize Spanish Florida and Louisiana with British and Indian help. Although the Senate expelled Blount the following day, the House persisted with its impeachment plans.
On February 5, 1798, as eleven House managers prepared to present five articles of impeachment against Blount, the Senate adopted a rule to ensure their respectful reception. This very first Senate impeachment rule provided that "All persons are commanded to keep silence while the Senate of the United States are receiving articles of impeachment against ___ ___ on pain of imprisonment."
Four days later, following delivery of the impeachment articles, the Senate adopted an oath, as required by the Constitution, binding members to "do impartial justice, according to law." This action followed a bitter debate that raised significant questions about the Senate's power to set its own impeachment rules. Federalist senators, who held a nearly two-to-one majority, contended that the Senate could establish such an oath by simple resolution. The opposing Jeffersonian Republicans, supported by several Federalists, responded that the Senate had no right to set its own oath. In their view, such action must be accomplished like any other legislation, by statute with the necessary involvement of the House and president. Otherwise, they warned, an impeached party might "deny the jurisdiction of the Senate, sitting under an oath of their own making," and some senators might refuse to take an improperly established oath. Citing state legislative precedents and the constitutional provision granting to the Senate sole Power to try all Impeachments, the Federalists prevailed in their determination that the Senate should have complete authority to set the rules for such trials. Congress then adjourned for ten months.
When the Senate reconvened in December 1798, it adopted additional impeachment rules. Drawn from British parliamentary and American colonial and state practice, these rules serve as the earliest foundation for those in effect today. On January 11, 1799, the Senate dismissed the impeachment case against Blount since he no longer held office.
Melton, Bruckner F., Jr. “Federal Impeachment and Criminal Procedure: The Framers’ Intent.” Maryland Law Review 52 (1993): 437-57.