By Matt Wells
BBC News, Connecticut
The leafy streets of New Haven are an unlikely venue for Democratic in-fighting over Iraq, that might see one of its best-known senators effectively ousted from the party in a few weeks' time.
'Insurgent' Ned Lamont is winning support from liberal Democrats
Senator Joe Lieberman has been representing Connecticut for 18 years now in Washington and, aside from almost snatching the vice-presidency in 2000 as Al Gore's running-mate, he also ran for president in 2004.
But after years of supporting President George W Bush's war policy, and scolding fellow Democrats who question it, he now faces a backlash from local anti-war activists and liberal bloggers all over the country.
In May, a little-known millionaire cable television executive, Ned Lamont, won the right to challenge Lieberman for the Democrat nomination, in a special state primary election on 8 August.
Only voters registered with the party can take part; the full US mid-term elections take place in November.
Born January 1954, Washington DC
Graduate of Yale and Harvard
Set up Lamont Digital Systems, 1984
Has never held elected office
What has turned this local political tussle into a contest of national significance is the fact that Mr Lamont has become a standard-bearer for activists who believe the Democratic leadership lacks any coherence over Iraq.
Mr Lamont has a sophisticated campaign operation already in full gear, and looks every inch the professional politician, despite his lack of even state-level experience.
His popularity is growing rapidly, according to opinion polls.
Faced with Mr Lamont's challenge, Mr Lieberman has said he will run as an independent if he loses the primary - in which case he would "stay a Democrat" even without the party's backing.
Enemies of 'Bush lite'
A polished stump speech by Mr Lamont at a recent rally in a New Haven hotel ballroom drew cheers from hundreds of excitable supporters.
The audience were not from the suburban moderate mainstream. They view Senator Lieberman through the lens of betrayal: a politician who they characterise now as "Bush Lite".
"We're staunchly anti-war, we'd like to get a Democratic senator that actually represents Democratic values," said one woman, who left the Green Party just so she could vote Lamont.
"This boat needs rocking," she added angrily, referring to senior party figures in Washington who have publicly endorsed Lieberman for another term.
Among the liberal heavyweights lending their support from the podium in New Haven, were Democracy for America's Jim Dean - brother of Democratic National Committee chairman, Howard Dean - and Eli Pariser, the executive director of MoveOn.org.
Opposition to the senator's unwavering support for the "stay the course" strategy in Iraq permeates the Democratic insurgent's entire pitch.
1942: Born in Stamford, Connecticut
1970: Elected to Connecticut State Senate
1983: Elected as Connecticut attorney general
1989: Wins bid for US Senate
2000: First Jewish candidate for vice president
Unsuccessful bid for 2004 presidential nomination
"I felt fundamentally that the Bush administration has taken the country in the wrong direction - that Joe Lieberman was undermining the Democratic message and providing an awful lot of cover, and I thought somebody should stand up," Mr Lamont told the BBC.
One seasoned Lieberman-watcher, Mark Davis, who is the political editor for the ABC-network affiliate in Connecticut, said the ballroom supporters were a powerful voice in the Democratic Party, but not the electorate at large.
"The liberal wing always does well in primaries, and that's why it looks like Lamont's got more support than perhaps he actually does."
It was important not to underestimate the power of incumbency, and healthy campaign coffers, he added.
"Joe Lieberman has got $8m in the bank. Ned here may be a millionaire, but so far he's only committed to spending a million of his own dollars."
Senator Lieberman, meanwhile, is standing by his convictions and on his high-profile record of service to the state.
Mike Picarello: Lieberman is 'too pro-Bush'
"On Iraq, I've done it not for reasons of increasing my political popularity. I'm doing it because I think it's right," he told National Public Radio.
But out on the streets around New Haven Green - which borders the Oxbridge-style buildings of Yale University - it was hard to find any Democrat voters who felt the senator was doing the right thing.
"Through the years, he's been a great senator but he's a little bit too pro-Bush on the war - big mistake," said Mike Picarello, who runs a local sandwich shop.
"I think a challenge is good," he added, although he has not yet made up his mind whether to back Mr Lamont.
When Howard Dean was running for the presidency two years ago, the mainstream media leapt at the net-roots' activism that it spawned, before helping to bury the candidate, after the celebrated "Dean scream" in Iowa.
A Connecticut primary is a far more manageable field and, after attending a Lamont rally in a trendy New York bar, it is clear that hundreds of liberals from out-of-state will be donating both money and time to the cause over the coming weeks.
Mr Lieberman, who is an Orthodox Jew, has no choice but to take this first primary challenge of his long senate career very seriously.
He has said he plans to collect the 7,500 signatures needed to run as an independent as an "insurance policy", thus ensuring his presence on the ballot paper in November whether or not he wins the Democratic nomination.
"While I believe that I will win the 8 August primary, I know there are no guarantees in elections," he said.
"I want the opportunity to put my case before all the people of Connecticut in November."
Conservative support across party lines may well be enough to send him back to Washington.