Sen. Joe Lieberman on Monday became the fifth member of the Senate Democratic Conference to publicly oppose President Barack Obama’s tax cut plan.

In a statement that was to be delivered to a local Chamber of Commerce, the Connecticut Independent Democrat said he does not want to let taxes on the rich increase next year by extending George W. Bush-era tax cuts only for the middle class.

“I don’t think it makes sense to raise any federal taxes during the uncertain economy we are struggling through,” Lieberman said. “I will do everything I can to make sure Congress extends the so-called Bush tax cuts for another year and takes action to prevent the estate tax from rising back to where it was.”

He said wealthier taxpayers are typically those who invest or make major consumer purchases.

“I know that many people, including the President, have argued that the tax cuts should not be continued for people making more than $200,000 a year, but to me these are the people we need to be using their income to spend and invest to spur growth and job creation,” Lieberman said. “The fact is that the top 3% of American income earners account for 25% of the consumption in our economy. Remember consumer demand is still the major driver of economic growth in America. I want the top income earners in our country to have the confidence and the money to spend and invest over the next year, rather than worrying about paying more in taxes to the federal government.”

Obama is pushing Congress to extend the Bush tax cuts for individuals making under $200,000 or couples making $250,000 and let the rest of those cuts from 2001 and 2003 expire. Obama argued last week that the country cannot afford more tax cuts for the rich.

Lieberman’s position only makes it more difficult for Senate Majority Leader Harry Reid (D-Nev.) as he seeks to round up the 60 votes needed to break an expected GOP-led filibuster of a middle-class tax-cut extension.

None of the 41 Senate Republicans has signaled a willingness to vote for the Obama plan, and Democratic Sens. Jim Webb (Va.), Ben Nelson (Neb.), Evan Bayh (Ind.) and Kent Conrad (N.D.) have made arguments similar to Lieberman’s in announcing their opposition to the president’s proposal.