Lieberman leaves behind a long and accomplished but mixed legacy. Early-career accomplishments as a champion of progressive causes were completely wiped away by his late-life lurch to the right. He was steadfast in his support of the disastrous invasion and occupation of Iraq, and he nearly killed the Affordable Care Act. While he continued to caucus with Democrats as an independent, he too often aligned himself with Republicans on key issues to be remembered as any type of hero to the left.
Lieberman was a New Deal Democrat who was concerned with liberal social policies and civil rights, but he was willing to take unpopular stands in his party. Despite Democrats' intolerance of his support for the Iraq War, he held firm to his beliefs, knowing how crucial it was for the US to fight terrorism abroad. He endorsed Republican John McCain in the 2008 presidential race and even had nice things to say about former Pres. Donald Trump — proving there can be a middle ground in US politics. He has an important political legacy.