"If you're disappointed with the ugly tone of our politics, if you're fed up with the nasty partisanship in Washington, then I ask your help, too," said Lieberman, who was criticized as being too close to the Republican administration.
Lieberman called on people across America to visit his Web site and send ideas "on how we can build this new politics of unity and purpose." He also hit them up for campaign contributions.
"Together I am confident that we can find common ground and secure a better future for our children," he said. "That, and not partisanship, is what our politics ought to be about."
The next day, Lieberman discussed his decision to run as an independent before a national audience on CNN's "Larry King Live."
Lieberman's plea to voters beyond Connecticut comes as many Democratic Party leaders in and out of the state are abandoning the three-term incumbent and publicly endorsing Lamont. Several have urged Lieberman to withdraw from the race.
However, the centrist Democrat has the benefit of being well known outside his state. Aside from being the Democratic vice presidential candidate in 2000 and a presidential hopeful in 2004, Lieberman also is part of the so-called Gang of 14, the bipartisan group of moderate senators who have tried to work together on various issues.
"Lieberman has a national reputation. He was on a national ticket, he's regarded by at least the Sunday talk shows as one of the senators who typically makes the circuits. So he has somewhat of a national following," said Ken Dautrich, a University of Connecticut public policy professor.
Though the appeal to a national audience is an unusual move for a state election, Dautrich said it makes sense for Lieberman. He said Lamont has already benefited from national support, including MoveOn.org, the liberal Internet-based organization whose members have contributed more than $250,000 to the anti-war candidate.
"Even though this was a Connecticut election among Democratic voters, it really had a national flavor to it given all the attention it got," Dautrich said.
Lieberman has come under fire for his support of the Iraq war and a perceived closeness with President Bush and Republicans. Lamont capitalized on that ill will and portrayed Lieberman as being out of touch on the war and key Democratic issues such as health care coverage and education spending.
Lamont's campaign said Lieberman's pitch to people outside the state is an example of the senator trying desperately to hold on to power.
"He didn't like the decision of the voters of Connecticut so he's appealing to people outside of Connecticut," said Liz Dupont-Diehl, campaign spokeswoman.
According to the Center for Responsive Politics, about 46 percent of Lamont's campaign funds have come from inside Connecticut while 54 percent came from outside the state. That doesn't include the more than $4 million the multimillionaire cable company founder has contributed himself, making up 61 percent of his campaign's funds.
Seeking more cash from outside the state isn't a stretch for Lieberman. About 80 percent of his campaign funds have come from outside Connecticut, according to the center. He has about $2 million left over from the primary, according to campaign spokesman Dan Gerstein.
Eighty-two percent of Lieberman's contributions came from individuals and 16 percent from political action committees. Lamont is not accepting contributions from political action committees.
Lieberman said his message of "progressive new ideas and stronger national security" resonates with people across the nation. Now he needs those people to help out, especially since Lamont could dump more of his own money into the now-three-way race with Lieberman and Republican Alan Schlesinger.
"This is saying to a lot of people across the country, who I know are as fed up as I am with the partisanship in Washington that stops our government from doing anything about the big problems that average people face," he said Thursday.