The Immortal Thirteen were the Democratic members of the state Senate in the 1841-42 session of the general assembly. These thirteen Democrats maintained a one-seat majority in the Senate, but the rival Whig Party's majority in the House of Representatives gave that party a two-vote advantage in a joint session of the legislature. Traditionally, the general assembly elected U.S. senators in a joint session, but with both Senate seats vacant, the “Thirteen” attempted to use their edge in the state Senate to force Whigs to accept a Democrat's election to at least one of the national seats. Thus, they refused to meet with the House in a joint session and claimed that the U.S. Constitution required senatorial candidates to receive approval from both chambers in their separate capacities.
Hailed as the “Immortal Thirteen” by their party, the Democratic senators' stance backfired. Whigs refused either to accept a Democrat's election or to compromise on the mode of election, while few voters found plausible the Thirteen's claim to have discovered the true interpretation of the Constitution. Despite numerous efforts, Democrats could find no honorable way to retreat from their position. The controversy ultimately consumed the session and prevented the passage of any substantial legislation. No senators were elected before the session's adjournment, and Tennessee remained unrepresented in the U.S. Senate for two years. The controversy proved a major liability for Democrats in the 1843 state elections, in which Whigs won control of both chambers and subsequently elected Ephraim Foster and Spencer Jarnigan to the U.S. Senate.