He allowed the Senate to freely conduct debates and confined his participation to procedural issues, which he called an "honorable and easy" role.[150] Jefferson had previously studied parliamentary law and procedure for 40 years, making him quite qualified to serve as presiding officer. In 1800, he published his assembled notes on Senate procedure as A Manual of Parliamentary Practice.[151] He cast only three tie-breaking votes in the Senate.
In four confidential talks with French consul Joseph Létombe in the spring of 1797, Jefferson attacked Adams and predicted that his rival would serve only one term. He also encouraged France to invade England, and advised Létombe to stall any American envoys sent to Paris by instructing him to "listen to them and then drag out the negotiations at length and mollify them by the urbanity of the proceedings."[152] This toughened the tone that the French government adopted toward the Adams administration. After Adams's initial peace envoys were rebuffed, Jefferson and his supporters lobbied for the release of papers related to the incident, called the XYZ Affair after the letters used to disguise the identities of the French officials involved.