Joseph Isadore "Joe" Lieberman (born February 24, 1942) is a United States Senator from Connecticut. Lieberman was first elected to the United States Senate in 1988, and was elected to his fourth term on November 7, 2006. In the 2000 U.S. presidential election, Lieberman was the Democratic candidate for Vice President, running with presidential nominee Al Gore, becoming the first Jewish candidate on a major American political party presidential ticket. He and his running mate won the popular vote, but failed to gain the electoral votes needed to win the heavily controversial election. Lieberman ran for re-election to the U.S. Senate while he was also Gore's running-mate, and he was re-elected by the voters of Connecticut. He attempted to become the Democratic nominee in the 2004 Presidential election, but was unsuccessful.

During his reelection bid in 2006, he lost the Democratic Party primary election, but won reelection in the general election as a third party candidate under the party label "Connecticut for Lieberman." Lieberman is now officially listed in Senate records for the 110th Congress as an "Independent Democrat", . and sits as part of the Democratic Senate caucus in the 110th Congress.

Lieberman has been one of the Senate's strongest advocates for continued prosecution of the Iraq War. He is also a consistent supporter of Israel. On domestic issues, he strongly supports free trade economics. He has also opposed fillibustering Republican judicial appointments. With Lynne Cheney and others, Lieberman co-founded American Council of Trustees and Alumni (ACTA), an educational association with ties to Campus Watch. Lieberman has also voted with Republicans on some ethical issues, and is one of the Senate's leading opponents of violence in video games and on television. Lieberman describes himself as being "genuinely an Independent," saying "I agree more often than not with Democrats on domestic policy. I agree more often than not with Republicans on foreign and defense policy."

Lieberman was elected as a "reform Democrat" to the Connecticut Senate in 1970, where he served for 10 years, including the last six as Majority Leader. He suffered his first defeat in Connecticut elections in the Reagan landslide year of 1980, losing the race for the Third District Congressional seat to Republican Lawrence Joseph DeNardis, a state senator from suburban Hamden with whom he had worked closely on bipartisan legislative efforts. From 1982 to 1988, he served as Connecticut's 21st Attorney General and emphasized consumer protection and environmental enforcement.