Lieberman, Conrad Retiring: Who's Next? Former Democrat is one of the few remaining moderates in the U.S. Senate.

Jan. 18, 2011 -- One day, two retirements.

Senator Joe Lieberman called Senator Majority Leader Harry Reid on Tuesday to tell him he is not running for re-election in 2012. That's actually good news for Democrats. Although the Independent Lieberman is a member of the Democratic caucus, his decision to retire makes it easier for Democrats to hang on to his Connecticut Senate seat.

If Lieberman had run, he would have almost certainly run as an independent. That would have meant a three-way race, giving Republicans their best – and perhaps only – shot at winning the seat in a state President Obama won in an 22-point landslide in 2008. Now Connecticut Democrats will have a chance to unite behind a single candidate.

The day's other retirement, however, is terrible news for Democrats. Senator Kent Conrad D-N.D. would have faced a tough re-election campaign, but he would have been, by far, the best chance for Democrats to hang on to the seat. North Dakota is a solidly Republican state that went for John McCain in 2008 and last year elected Republican John Hoeven to the Senate with 76 percent of the vote.

A Lieberman aide says that the Senator will formally announce his decision on Wednesday by quoting the Old Testament book of Ecclesiastes: "To everything there is a season, and a time to every purpose under the heaven."

In this Senate, this is the season of retirement. At least a dozen Senators who are up for re-election have not declared whether they intend to run for re-election. Based on discussions with campaign strategists in both parties, here are the top prospects for retirement --

1. Daniel Akaka D-Hawaii – Akaka will be 88 years old by Election day 2012. As of the last fundraising report, Akaka's campaign account had only $75,000 on hand. And although Hawaii is a Democratic state, he could face a potentially tough challenge from Linda Lingle, the state's first Republican governor, who is considering a run for Senate.

2. Jim Webb D-Va. – Webb won a narrow victory over Sen. George Allen in 2006 and would face a tough re-election battle this time around. He hasn't done much fundraising yet and, so far, isn't behaving like somebody gearing up for a tough campaign. One caveat: George Allen announced Tuesday that he will run to get his old seat back. Democrats close to Webb say the prospect of a re-match might actually make it more likely that Webb will run again.

3. Jeff Bingaman D-N.M. – The 67-year-old Bingaman has been in the Senate 28 years. He hasn't raised much money yet and has yet to announce his intentions.

4. John Ensign R-Nev. – Tainted by a sex scandal (he admitted having an affair with the wife of one of his senior aides), Ensign will face a bruising Republican primary if he decides to run. Many Republicans expect – or at least hope – he will decide not to run.

5. Jon Kyl R-Ariz. – He's the number two Republican in the Senate, but Kyl has been coy about his re-election plans. And, although he could raise money quickly, he has only $619,000 in his campaign war chest, a far cry from the $16 million he raised in the last campaign. Senate Republicans tell me they don't know what he plans to do.

6. Ben Nelson D-Neb. – Nelson is acting like somebody who plans to run for re-election. He's been busy fundraising ($1.4 million in the bank as of Sept. 30) and staking out positions that put him at odds with his party but, theoretically, play better in Nebraska. But Nebraska is a strongly Republican state and Nelson will pay a high price for one key vote where he did toe his party's line: in favor of the health care bill. If the race looks hopeless, he may opt for a smoother exit.

7. Herb Kohl D-Wisc. – Kohl, 75, is one of the richest Senators, and one of the quietest. He's given no indication yet whether he plans to run for re-election or devote more time to the Milwaukee Bucks basketball team, which he owns.