Former U.S. senator and vice presidential candidate Joe Lieberman has died at the age of 82.
A family statement obtained by the BBC's US partner CBS News said the cause was complications from a fall.
The centrist represented Connecticut in the Senate for nearly a quarter of a century.
Lieberman was Al Gore's vice presidential candidate in 2000, making him the first Jew to run for a major party in the U.S. presidential election.
Mr. Gore said he was “deeply saddened” to learn of Mr. Lieberman's death.
“It was an honor to stand alongside him on the campaign trail,” Gore said in a statement. “I will forever be grateful for his tireless efforts to build a better future for America.”
A longtime politician, he served as a senator from Connecticut from 1989 to 2013. He was an influential congressman, and his support was sought in Washington.
“Senator Lieberman's love for God, family, and America continued to serve the public interest throughout his life,” the family said in a statement.
A longtime Democrat, he left the party over several issues, including his opposition to the Iraq War. He won his final term as an independent in 2006.
In recent years, he was known as the founding chairman of No Labels, a centrist political group that aims to establish a third-party presidential candidate for the 2024 general election.
“Senator Lieberman has been a unique figure in American politics who has always put his country above his party,” the third-party political group No Labels said in a statement Wednesday.
Lieberman made the revelation in a recent interview with Bloomberg TV last week.
“Thomas Jefferson once said that America needs a little political rebellion every now and then, that it should be as important in politics as it is in natural storms.”
“And I think he was going to clear out the dead wood. And, hey, does our political system need a big storm and a political revolt right now?”
Mr. Lieberman was born in Stamford, Conn., in 1942 and was active in state politics, serving as a state senator and state attorney general before running for the U.S. Senate in 1989.
Mr. Lieberman was one of the most prominent Jewish politicians in the United States during his lifetime. Running for the White House with Gore was a milestone for Jewish Americans, with the former senator publicly demonstrating his faith.
As a moderate Democrat, Mr. Lieberman developed a reputation in Washington for going beyond party lines and beyond just members of his own party.
In 2000, Mr. Gore selected Mr. Lieberman as his running mate for the Democratic presidential nomination. They subsequently lost to Republican George W. Bush and running mate Dick Cheney, resulting in one of the most controversial presidential election outcomes in American history.
But by 2008, Mr. Lieberman was endorsing the Republican presidential candidate, Sen. John McCain of Arizona, who was a close friend.
McCain would ultimately lose to America's first black president, Barack Obama.
As a senator, Lieberman also supported several progressive policies. He was particularly instrumental in repealing the Pentagon's “Don't Ask, Don't Tell” policy, which prohibited LGBTQ people from openly serving in the military.
In his farewell speech on the Senate floor, Lieberman said, “As I look back over my career, the accomplishments I am most proud of in my legislative work…all came from a significant number of Democrats and Republicans who agreed.'' This was achieved because we found the point.” December 2012.