(Joshua Roberts/BLOOMBERG)

The CBO said in a Tuesday night letter to Boehner that the speaker’s plan would achieve about $850 billion in deficit savings over the next decade, not the $1.2 trillion touted by House GOP leadership since the proposal was unveiled Monday night.

A Boehner spokesman said Tuesday night that congressional staffers were currently reviewing ways to rework the measure in order to achieve the amount of cuts originally pledged.

“We’re here to change Washington – no more smoke-and-mirrors, no more ‘phantom cuts,’” said Michael Steel, a spokesman for Boehner. “We promised that we will cut spending more than we increase the debt limit – with no tax hikes – and we will keep that promise. As we speak, Congressional staff are looking at options to re-write the legislation to meet our pledge. This is what can happen when you have an actual plan and submit it for independent review – which the Democrats who run Washington have refused to do.”

News of the CBO report came shortly before House Republicans were set to hold a closed-door conference meeting at 7 p.m. in a room in the Capitol basement.

Despite a veto threat by President Obama, Boehner’s plan would raise the country’s $14.3 trillion debt ceiling in a two-step process. The CBO report is based on the first stage of that process, which would allow the debt ceiling to be raised by roughly $1 trillion and avert a potentially catastrophic default by Aug. 2.

The report seriously endangers the chances that the debt-limit proposal will pass the Republican-controlled House on Wednesday, less than a week before the deadline by which Congress must pass a measure to raise the legal borrowing limit. The proposal has already been met with opposition from House conservatives who have argued that it does not slash deeply enough, and upping the stakes for Boehner is the fact that few House Democrats are expected to support the bill.

“I would much prefer ‘cut, cap and balance’ to this; I’d like to get a Constitutional amendment requiring us to balance the budget ... but it doesn’t look like we’re going to get it at this point,” said Rep. Steve Chabot (R-Ohio).

Chabot was referring to a plan that passed the House last week with support from many House conservatives. It would cut and cap government spending, as well as implement a balanced budget amendment to the Constitution. Nonetheless, Chabot said was leaning toward supporting the Boehner two-step plan.

Asked whether Senate Majority Leader Harry Reid’s (D-Nev.) competing debt-limit proposal was a factor in his thinking about the Boehner plan, Chabot said that it was.

“Yeah, and that’s one of the reasons why I’m inclined to support it, because of that very thing,”he said, adding that he believed that if Wednesday’s vote failed, it would give Reid leverage.

“The alternative is Harry Reid’s, and I don’t think that goes nearly far enough.”

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