Sen. Tom Carper (D-Del.), a close ally of Sen. Joe Lieberman, said the Connecticut Independent should pay a price for his campaign attacks against President-elect Barack Obama.

"There need to be consequences, and they cannot be insignificant," Carper said in a Monday interview with The Hill.

Lieberman said he supported Sen. John McCain (R-Ariz.) because he was the best prepared to lead the country at a time of war, and Lieberman questioned Obama’s readiness to lead.

Carper did not rule out stripping Lieberman of his coveted gavel running the Homeland Security and Governmental Affairs Committee, or imposing other sanctions like taking away seniority on other committees or a subcommittee on Armed Services.

Carper said he and three other Senate Democrats have been making phone calls to "take the temperature of our caucus." He said the purpose of the calls was not to lobby senators for any particular action for or against Lieberman, but "just to see where people's hearts and their minds are.”

Carper said that "many of my colleagues ... are very angry with his criticism of Sen. Obama," but he would not say which sanctions he prefers.

Lieberman has threatened to leave the Democratic Conference and organize with Republicans if Democrats impose too harsh of sanctions. But Carper said he was "not sure" how Lieberman would react to tough penalties, and said Lieberman will have to make his case before his Democratic colleagues at a closed-door meeting Tuesday.

"He'll have the opportunity to speak to our caucus tomorrow, and he just needs to speak from the heart," Carper said. "We'll see how it goes."

Before Democrats hold a secret vote on his future within the caucus, Lieberman is expected to explain his actions during the campaign and make his case that he wants to help Obama advance his agenda. Some Democrats fear he may work to undermine Obama as chairman of a powerful committee, but others worry that imposing too harsh of a penalty could alienate Lieberman, who could exact revenge by refusing to give Democrats his support to break GOP filibusters on major legislative matters.

Sen. Bill Nelson of Florida, another Democrat making calls on Lieberman's future, said reaction from his colleagues has generally been "positive," but would not elaborate on his discussions and did not know how the caucus would vote Tuesday.]

"Genetically he's a Democrat, and that's where he's comfortable and that's where he should be," Nelson said in an interview.

But Carper said Lieberman's actions have left a bad taste in the mouth of his colleagues. Carper said he urged Lieberman not to attend or speak at the Republican National Convention, and warned Lieberman against criticizing Obama there and on the campaign trail. In his speech praising McCain's foreign-policy experience and bipartisan record, Lieberman questioned Obama's readiness to be president and said he voted to cut off funding for troops in harm's way.

"I'm very disappointed as a friend and a colleague," Carper said.