Sen. Joe Manchin on Tuesday announced, in a speech in South Charleston, that not only will he support legislation that places tight caps on spending, but he will also lend his 'aye' vote to a constitutional balanced budget amendment, both measures opposed by Senate Democratic leadership.

"I believe that both the CAP Act and Balanced Budget Amendment offer a good framework for a bipartisan debt fix," Manchin said, "But let me be clear that one of my top priorities will be to make sure that any debt fix keeps our promises to seniors and protects Social Security and Medicare."

The West Virginia Democrat, facing what could be a tough re-election fight in a state where the president is deeply unpopular, previously promised not to support raising the country's $14.3 trillion debt ceiling unless the Senate approves a deficit and debt reduction plan. The Tuesday speech, part of Manchin's "Commonsense Solutions" week, shed further light on that promise, though it did not overtly make his support conditional on the two measures' passage.

Manchin spokeswoman Emily Bittner told Fox News, "He thinks they're both a good start to build the framework. He needs to see a fix in place to raise it, and supports both of these."

The National Senatorial Committee (NRSC), the GOP's campaign arm, wasted no time in accusing the senator of "political maneuvering," bashing him for supporting the president's economic stimulus plan (though the senator was not yet a member when the bill was approved), and health care reform. NRSC spokesman Brian Walsh further added, ""This is another clear difference between the rhetoric Senator Manchin offers to voters in West Virginia, versus the reality of his voting record in Washington."

The Manchin stance makes it clear, though, that no debt ceiling vote will occur without significant debt reduction strings attached, putting the White House in a difficult dilemma. Administration officials, led by Treasury Secretary Tim Geithner, have painted a Doomsday scenario should the borrowing cap not be lifted.

Manchin's support will not likely alter the fate of either provision, though, as support for both spending caps and a constitutional amendment is significantly low among Democrats who control the chamber.  Only Missouri's Claire McCaskill, a CAP Act author, supports both measures.

Joe Lieberman of Connecticut, an Independent who tends to vote with Democrats, supports spending caps. And Mark Udall of Colorado has signed onto the balanced-budget amendment. Without significantly more support -- 67 votes are needed for BBA and 60 for the CAP Act -- both measures stand no chance of passing, though Republicans have threatened to hold up the business of the Senate unless the measures are considered.

But the fate of the bills could change as polls show that raising the debt limit is unpopular with voters. And 61 percent of Americans said they favored a constitutional amendment in a recent NBC News-Wall Street Journal poll.

The CAP Act, the brainchild of Sen. Bob Corker, R-Tenn., would force federal spending over 10 years down to 20.6 percent of GDP. It's around 25 percent now.

The Manchin's comments are part of a growing chorus of centrist Democrats uneasy about the nation's debt problem. Senate Budget Committee Chairman Kent Conrad, D-ND, a member of bipartisan negotiations aimed at producing a plan for significant debt reduction, recently said he would oppose a longer-term debt ceiling increase without that plan or something similar.

As members return next week from an Easter recess, it's clear, the White House and Democratic leaders will have their work cut out for them.