Bradley, the former senator from New Jersey, endorsed Dean at a rally in Manchester, N.H.
"In 2000, many Americans in Iowa and New Hampshire and across the country gave me their support, and I continue to consider their confidence a sacred trust," Bradley said. "This year many of them have asked me who among this very capable group of candidates I would recommend. My answer is Howard Dean."
Bradley added that the "Dean campaign is one of the best things that's happened to American democracy in decades."
Bradley further said that Dean "supporters are breathing fresh air into the lungs of our democracy. They're revitalizing politics, showing a way to escape the grip of big money and to confront the shame of forgetting those in need."
Bradley served in the Senate from 1979 to 1996. A Rhodes scholar and former all-American college basketball player, Bradley also played professional basketball for the New York Knicks.
Dean called Bradley a "thoughtful, careful person who sought to lead this country with honor and integrity and who stood up against the same forces that we're standing up against in Washington."
Meanwhile, on Monday in Nashua, N.H., Clark unveiled what his campaign has dubbed the "Families First Tax Reform plan." The plan would eliminate the income tax for families making up to $50,000 per year, while families making up to $100,000 per year would get a tax cut.
"Right now, the sad fact is that too many Americans are working harder and harder and earning less and less. Under George W. Bush, the typical working family has seen its income fall by nearly $1,500," Clark said. "Compare that to the eight years under President Clinton, when the typical family saw its income rise by $7,200."
The Clark plan, according to a summary posted on the candidate's Web site, would also combine the current Child Tax Credit, the Additional Child Tax Credit, the Earned Income Tax Credit, and the Dependent Exemption and expand them to provide a $2,250 tax credit per child.
"The entire proposal is offset by closing corporate loopholes and by a 5 percentage point rate increase on income over $1 million a year," the summary states. "The rate increase will only reach the income over $1 million of the top 0.1 percent of taxpayers."
Presidential contender Sen. John Kerry, D-Mass., also unveiled a tax and jobs plan this week that aims to help middle class Americans. A main component of Kerry's plan is to stop companies from "outsourcing" jobs to cheaper labor markets abroad.