"While I understand that Sen. Lieberman has voted with Democrats a majority of the time, his comments and actions have raised serious concerns among many in our caucus," Reid said.
Lieberman was Democrat Al Gore's vice presidential running mate eight years ago. He switched to an independent after he failed to win the Democratic Senate primary in Connecticut in 2006. Lieberman won the general election as an independent but is still registered as a Democrat.
Connecticut Democrats are scheduled to meet on Dec. 17 to decide whether the state party should censure Lieberman.
"It will come up but I'm certainly waiting to see what's going to be happening in the Senate and I'm certainly using that as a barometer," said Nancy DiNardo, the party's state chairwoman.
Although he aligns himself with Senate Democrats, Lieberman angered many Democrats for when he used a prime-time speech at the Republican convention this summer to criticize Barack Obama as an untested candidate beholden to Democratic interest groups. Republican McCain had considered making Lieberman, a longtime friend, his running mate this year before settling on Alaska Gov. Sarah Palin.
Bouncing Lieberman from his committee post would require the approval of the Democratic caucus, which is expected to meet this month.
"I want to spend some time in the next few days thinking about what Sen. Reid and I discussed what my options are at this point," Lieberman said. "He promised me that he would do the same and we would continue these conversations."
Republicans have said they would welcome Lieberman to their caucus.
Democrats in the past had tolerated Lieberman's political straddling because he held their slim 51-49 majority in his hands. Now that Democrats have strengthened their hold in the Senate to at least 55 seats as a result of Tuesday's election, Lieberman no longer is vital to their majority control.
Despite splitting with most Democrats on the war in Iraq, Lieberman tends to vote with them on domestic issues such as health care, education and the environment.
