A former Democratic congressman who sat across from Paul Ryan on a major bipartisan budget deficit commission said Mitt Romney's running mate took a hard line on fundamental economics issues and never fully committed to negotiating a deal.

"Paul drifted -- he came to all the meetings, and kept asking pertinent questions, but his heart wasn't in it," said John M. Spratt, a recently retired member of Congress from South Carolina who served with Ryan on the Simpson-Bowles Commission in 2010. "Eventually, he just went back to what he was doing before, back to developing the roadmap, working for his party and not for bipartisanship."

The Simpson-Bowles commission was a high-profile effort by President Obama to reach bipartisan agreement on reducing the budget deficit. It eventually failed to reach a consensus, largely owing to the opposition of fiscal conservatives, even though many officials in both parties continue to tout the wisdom of its recommendations.

In fact, in an interview in early August, presumptive Republican presidential nominee Mitt Romney said his own deficit reduction plan "is very similar to the Simpson-Bowles plan."

For many months, Erskine Bowles, the commission's Democratic co-chair, "bent over backwards trying to accomodate" Ryan, Spratt said. Had he succeeded in persuading Ryan, who had already emerged as a leading voice for fiscal conservatives, Spratt believes that the other two House Republicans would have come along.

"Paul really spent most of his effort [in Congress] building bridges within the Republican Party for a particular ideology that views all taxes as anathema," Spratt said. "Any package that has any taint of taxes involved in it, he's simply not interested in supporting."

Spratt also told HuffPost in a phone interview that Ryan -- and the depth of his conservatism -- is "not to be underestimated."

"He is intelligent, likeable, affable, and he is well to the right of center," Spratt said. "I remember when Dick Cheney ran for V.P., and people started looking into his background, what they found was that Cheney was a lot more conservative than he had appeared to be in public. I would say the same is true of Paul Ryan. Once the media and opposition dig into his voting record, I think they're going to be rather surprised how far to the right he is."

Brendan Buck, a campaign spokesman for Ryan, disputed the idea that Ryan was unwilling to work across party lines, pointing to his efforts to reform Medicaid and Medicare in the commission with Democrat Alice Rivlin. He added that Ryan voted against Simpson-Bowles "based on legitimate policy objections, not just taxes"

"While Congressman Ryan has worked tirelessly in a bipartisan manner to solve these challenges, President Obama has racked up record debt and deficits, and under this failed leadership America saw an unprecedented credit decline," Buck added.

Spratt's assessment of Ryan's negotiating style mirrors that of another Democrat who served across from Ryan on the House Budget Committee, Maryland's Chris Van Hollen.

In an interview a week ago on MSNBC, Van Hollen, who is now the committee's ranking member and poised to play Ryan in Vice President Joe Biden's debate prep, said that Ryan was civil but impossible to negotiate with on matters of principle.

"There's a distinction between civility and congeniality and willingness to compromise," Van Hollen said. "If you look at the Ryan Republican budget, it is a totally uncompromising document."

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