In a blow to President Barack Obama and Senate Democratic leaders, Sen. Joe Manchin will throw his support Tuesday behind strict new spending caps that would require far deeper cuts than they support over the coming decade.

The West Virginia Democrat will endorse a Senate bill that would impose caps starting in 2013 that gradually tighten spending to 20.6 percent of gross domestic product in fiscal 2022. Obama’s budget request aims to keep spending at about 24 percent of GDP, and a budget blueprint written by House Budget Chairman Paul Ryan (R-Wis.) would cut spending to about 20 percent. The House adopted Ryan’s measure this month.

The Senate bill, which is dubbed the Commitment to American Prosperity Act, is sponsored by Sens. Bob Corker (R-Tenn.) and Claire McCaskill (D-Mo.), and it recently received the backing of Sen. Joe Lieberman (I-Conn.).

Manchin’s move puts majority Democrats closer to ceding control of the budget issue to Republicans. If one more Democrat joins all Republicans to back the CAP Act, the legislation would have majority support in the Senate.

Manchin is also endorsing a balanced-budget amendment to the Constitution.

In remarks Tuesday, he will reiterate that a long-term fix to the nation’s debt, like the CAP Act or the balanced-budget amendment, must be found before he will support an increase in the $14.3 trillion federal debt limit.

“There are some in Washington who will say this position is irresponsible, that it jeopardizes our economy and our markets,” Manchin is expected to tell West Virginians, according to prepared remarks. “Amazingly, Washington is the only place where agreeing to trillions of dollars of additional debt and avoiding difficult budget decisions is the ‘responsible’ thing to do. The truth is, raising the debt ceiling without a real budget fix would be the definition of irresponsibility.”

Should the CAP Act receive majority support in the Senate, Democrats would either have to filibuster it — an embarrassing move for the majority party — or hope for a presidential veto, should it reach Obama’s desk.

The move also greatly complicates the Senate’s ability to pass a budget resolution on Democratic votes. Spending caps similar to the CAP Act’s could be added to a budget resolution with a simple majority vote. Although moderate Democrats are making it clear they will not support a budget without tight new spending restraints, liberals will never go along with the deep cuts like those in the CAP Act.

Unlike Obama’s and Ryan’s budget resolutions, the CAP Act would create hard spending ceilings and would require automatic spending cuts across the government if they are exceeded. A two-thirds majority in each chamber would be necessary to waive the automatic cuts.

The CAP Act does not exempt Social Security or Medicare, but Manchin said he wants to ensure that seniors are somehow protected.

“One of my top priorities will be to make sure that whatever final debt fix emerges, it will keep our promises to our seniors by protecting Social Security and Medicare,” Manchin will say, according to the prepared remarks.