Washington - A few months ago, Sen. Joseph I. Lieberman, a Democrat, had a surprising guest at his office: Linda McMahon, the former wrestling mogul who is seeking the Republican nomination for Lieberman's Senate seat, now that he is retiring.

For about an hour, Lieberman gave a private briefing of sorts on a range of topics, including national security, to McMahon, who would no doubt benefit from adding political heft to her resume after a career at World Wrestling Entertainment, the company she steered with her husband, Vince.

"She's bright and likeable," Lieberman said in an interview, referring to McMahon.

Lieberman may not be running for re-election, but he is not content to fade away, it seems.

As candidates in both major parties begin jockeying for his seat, Lieberman has been doing and saying things that have confounded the political establishment - much as he has done in recent years.

In addition to McMahon, he has spoken with Christopher Shays, a former Republican congressman from Connecticut, about Shays' owns plans to run for his Senate seat.

"I encouraged him," said Lieberman, who met with Shays in his Washington office.

All this has exasperated liberals in Connecticut and Washington.

"Some of what he does seems designed to make it hard for progressives and the Democratic establishment to ignore him," said Jon Green, director of the Working Families Party in Connecticut. "But everyone does their best."

A top Democratic official in Washington was more pointed.

"I don't think he's interested in helping us," said the official, who spoke on the condition of anonymity because he did not want to cause tensions with the senator. "He's got a lot of resentment toward Democrats."

In the meantime, some Connecticut Democrats who are eyeing the party's nomination for his seat are staying clear of Lieberman. They seem wary of associating politically with a man who went from being the Democratic vice presidential candidate in 2000 to backing Sen. John McCain, R-Ariz., over Barack Obama, then a senator from Illinois, in the 2008 presidential race.

Susan Bysiewicz, a former Connecticut secretary of state who is seeking the Democratic nomination for Senate, noted in an interview that Lieberman was unpopular with rank-and-file Democrats.

"Sen. Lieberman's endorsement would not be helpful," she said, adding that she believed he was more closely identified with Republicans these days.

Rep. Christopher S. Murphy, a three-term Democrat who is also running for Lieberman's seat, said, "I'm not sure his support is relevant."

Despite meeting with Republicans, Lieberman said he would not get involved in the race and may not even endorse a candidate in either party.

But Lieberman noted that he had been friends with Shays for decades and that Shays, who lost his House seat in the 2008 election, was an independent-minded politician like himself. "I feel a personal connection to Chris," Lieberman said. As for encouraging Shays to run, he said that he is generally supportive of people who want to run for public office.

Lieberman also spoke admiringly of McMahon, though he noted that he had been publicly critical of World Wrestling Entertainment during a campaign he launched with William J. Bennett, a former United States education secretary, against indecency on television. (As a first-time candidate in 2010, McMahon ran for Senate and lost to Richard Blumenthal, a Democrat.)

Lieberman recalled that during their meeting, McMahon asked many questions and seemed informed. McMahon said she felt encouraged after the meeting. "He clearly felt that I brought a lot to the table and would make a fine candidate," she said.

Lieberman said he was not surprised that Democratic candidates were keeping their distance. "I don't expect any of them to ask for my support," he said. "And I understand why."

It was not always this way for Lieberman. The son of a liquor store owner, he entered politics as a Democrat in 1970, eventually becoming a respected figure largely because of his straightforward style and practical approach.

His major break with the party came in 2006, when he lost the Democratic nomination for Senate partly because of his staunch support of the Iraq war, as growing numbers of Democrats opposed it. He then ran and won as an independent in the 2006 general election. But his relationship with Democrats continued to sour, even though he caucused with the party in the Senate.

After campaigning against Obama in the 2008 presidential race, he publicly warned that he might join Republicans in derailing Obama's health care plan, though he supported the bill in the end. Yet he also antagonized Republicans by supporting Obama administration policies, including the repeal of the law banning gay men and lesbians from serving openly in the military.

It is unclear how much political sway Lieberman has with voters these days, but independent analysts and even Democrats acknowledged that Lieberman's support could be helpful to Republicans in a state that is heavily Democratic.

"The kind of Republican who wins in Connecticut is a moderate who is able to win independent votes," said Douglas Schwartz, the director of the Quinnipiac University Polling Institute. "Lieberman potentially helps reinforce a centrist image for the eventual Republican candidate."