The Connecticut Federation of Black Democratic Clubs, which includes 20 clubs across the state, endorsed Lieberman's Democratic rival Ned Lamont and questioned whether he marched for civil rights.
"Senator, the Connecticut Federation of Black Democratic Clubs is offended by your television ad which claims you were an advocate for African-Americans' first-class citizenship and as such you marched for our civil rights," said Henry E. Parker, a former state treasurer, during a news conference attended by Lamont.
"Our research indicates that there is no evidence of you taking any action that could be described as an initiative to remove the shackles of second-class citizenship," Parker said.
Lieberman's campaign produced a 1963 college newspaper clip that cites Lieberman's reporting from Jackson, Miss., about the arrests of civil rights workers. Lieberman was chairman of the Yale Daily News.