King touted himself as the antidote to the partisanship that drove Snowe, a Republican, to leave the bitterly divided Senate, which has failed to address many of those issues.
"She left because the place didn't function," he said. "She couldn't get anything done. She was utterly frustated. I think we need to do something different."
He said later he doesn't have any "magic formula" in Washington but "I think we've got to try."
Summers said he wants to reduce the size of government and to reduce the national debt by growing the economy.
"I want to go to Washington to lead the fight to cut spending, reduce regulations and keep taxes low so businesses can expand, so people can have jobs," he said.
Dill, a civil rights lawyer, described herself as a working mother who understands the middle class and would bring a breath of fresh air to a Senate that she says is dominated by wealthy white men.
"What's wrong with Congress is extreme wealth and extreme politics," she said.
Dalton, who's spent 25 years working for various federal agencies, said he wants to eliminate government waste and reform the tax code. Dodge, a tea party activist and libertarian, said rights were being trampled and he was ready to go to Washington to "smack a few heads together to get things done."