Sen. Joe Lieberman (ID-Conn.) on Sunday once again defended his decision to support Sen. John McCain (R-Ariz.) over President-elect Barack Obama in the White House election, but he said he regretted the harsh tone of the campaign and appreciated the “spirit of reconciliation” that prompted his Senate Democratic colleagues to allow him to keep his gavel on the Homeland Security and Governmental Affairs Committee.

Speaking on NBC’s “Meet the Press,” Lieberman said that he feels closer to the Senate Democratic Conference than he has since he lost the 2006 Democratic Senate primary in Connecticut and that his decision to relinquish his slot on the Senate Environment and Public Works Committee was not a disciplinary move but would allow newly elected Democrats to serve on the committee.

Lieberman said that Obama “has set exactly the right tone” since Election Day and that he looks forward to helping the president-elect succeed.

”We can’t afford the luxury of looking back,” he said.

But pressed by NBC’s Tom Brokaw on whether he would be willing to apologize to Obama and fellow Democrats, Lieberman hedged.

“I regret it,” he said. “I’m going forward. You can take from the word regret what you will.”