Correction: A previous version of this article said that Paul Ryan declined to comment. The Republican vice presidential nominee did decline requests for an interview, but it was not made clear that a spokesman for the Mitt Romney campaign, Michael Steel, provided a comment by e-mail.

GOP vice-presidential candidate and Wisconsin representative Paul Ryan speaks to supporters at a campaign event in Derry, N.H., on Saturday. (JESSICA RINALDI/REUTERS)

According to his pal Kevin McCarthy, vice presidential nominee Paul Ryan is “the thinker” of the GOP, the fiscal visionary with the plan to lead America out of debt and into the promised land of balanced budgets.

“Paul is knowledge,” said McCarthy (Calif.), the No. 3 Republican in the House leadership.

But knowledge is not action. Over the past two years, as others labored to bring Democrats and Republicans together to tackle the nation’s $16 trillion debt, Ryan sat on the sidelines, glumly predicting their efforts were doomed to fail because they strayed too far from his own low-tax, small-government vision.

As a member of an independent debt commission in 2010, Ryan voted against a bipartisan plan to cut borrowing by $4 trillion over the next decade by raising taxes as well as cutting spending. Through much of 2011, he insisted publicly that a “grand bargain” on the budget was impossible, even as House Speaker John A. Boehner (R-Ohio) pursued a deal with President Obama. And Ryan asked Boehner not to name him to the congressional “supercommittee” that took a final stab at bipartisan compromise last fall.

As chairman of the House Budget Committee, Ryan did draft a blueprint for wiping out deficits by 2040. And he has earned wide praise for tackling Medicare, the nation’s biggest budget problem, despite the political risk.

But as Washington braces for another push after the election to solve the nation’s budget problems, independent budget analysts, Democrats and some Republicans say Ryan has done more to burnish his conservative credentials than to help bridge the yawning political divide that stands as the most profound barrier to action.

“If you start with the premise, as Ryan does, that our current path is unsustainable, then you have to be willing to do something about it,” said Robert L. Bixby of the bipartisan Concord Coalition, which champions lower deficits. “Is it more important to prevent the debt from rising or to stick with your principles of lower taxes? So far, Ryan has chosen the purist route.”

Sen. Saxby Chambliss (R-Ga.), a close friend of Boehner’s who has been working with Democrats to try to bring a bipartisan debt-reduction plan to a vote in the Senate, agreed that Ryan had done little to advance the debate — “other than [offer] his budget, which was kind of a reiteration” of the blueprint he had previously proposed.

“I’ve never viewed Paul as one who gets into the fray from the negotiating standpoint,” Chambliss said. “I don’t mean that he can’t do it. I just mean that he’s chosen not to.”

Ryan declined to comment for this article. In an interview in November, long before his selection as Mitt Romney’s running mate, Ryan acknowledged his decision to stay away from the budget bargaining table in 2011, arguing that the supercommittee — and most other attempts at bipartisanship — were “a futile exercise” as long as Obama was in the White House.

Instead of pursing compromise, Ryan said that he had spent much of last year nurturing what he saw as “an emerging consensus on tax reform and Medicare reform” that could only take hold if Republicans reclaimed the presidency.

“We just have to win and fix this thing,” he said at the time. “2013 is the magic year that determines how all this gets resolved. And who’s running the place will determine that.”

Explore the 2012 electoral map and view historical results and demographics

Ryan’s unwavering dedication to conservative principles has impressed the party’s restive class of House freshmen. Rep. Allen B. West (Fla.) calls Ryan the “intellectual epicenter” of the GOP. But it has frustrated some of Ryan’s Republican colleagues, who have been forced to cut deals with Democrats to keep the government open and accomplish Republican goals, such as passing long-stalled free trade agreements. GOP aides noted that Ryan even voted against a measure, negotiated by House leaders, to dial back unemployment benefits and extend a temporary payroll tax holiday.

While Romney has characterized Ryan as a seasoned legislator with “an ability to work across the aisle” to “find enough common ground to get things done,” the seven-term Wisconsin congressman has no record of participating in any major bipartisan legislative achievement. Democrats say he would make a very different sort of vice president than Joseph Biden, a natural glad-hander who has taken the lead for Obama in negotiations with Republicans over taxes and deficit reduction.

“His approach — my way or the highway — is precisely what’s wrong with this town. It’s the triumph of ideology,” said Senate Budget Committee Chairman Kent Conrad (D-N.D.), who served with Ryan on the independent fiscal commission chaired by Democrat Erskine B. Bowles and former Republican senator Alan K. Simpson of Wyoming. “The hard reality is, given the fact that we have divided government, both sides have to compromise in order to achieve a result. And Paul has refused to do that.”

Ryan’s defenders say he has done the best he could given Obama’s lackluster leadership.

“As House Budget Committee Chairman, Paul Ryan — along with his colleagues — wrote and passed the only serious budgets Washington has seen in recent years,” Romney campaign spokesman Michael Steel said in an email. “He led the way on bipartisan deficit reduction proposals. At the same time, Senate Democrats failed to propose a budget at all, and President Obama’s budget received zero Democratic votes in the House or Senate.”

“I don’t think you can blame Paul” for the lack of movement over the past two years, said Sen. Lindsey O. Graham (R-S.C.). “His approach has been far more constructive than the president’s. He’s led.” If Democrats put a serious deal on the table, Graham said, “I think [Ryan] very much will embrace a compromise.”

Ryan, too, blames the president. “Obama didn’t want success,” he said in November. He said that became apparent seven months earlier when Obama responded to the recommendations of the Bowles-Simpson fiscal commission by rolling out his own deficit-reduction plan. Unaware that White House aides had invited Ryan to hear Obama’s speech at George Washington University — and that Ryan was sitting in the front row — the president blasted Ryan’s budget and renewed his call for higher taxes on the wealthy.

“It became clear to me when Obama invited us to GW . . . that he wasn’t going to triangulate and embrace Bowles-Simpson. He decided to double down on dema­goguery and ideology, and he has stuck to that ever since,” Ryan said.

While Ryan voted against the Bowles-Simpson plan, he said it offered hope for a consensus on debt reduction that would include a new tax code with lower rates, fewer loopholes and maybe “slightly” more money to fund the government — although not the $2 trillion the Bowles-Simpson plan called for over the next decade.

That consensus would also include fundamental ­changes to the “architecture” of Medicare, Ryan said, including partially privatizing the program so its cost “doesn’t just blow up on us” as the baby boom generation retires.

Ryan dismissed Obama’s offer to control Medicare costs, in part by raising the eligibility age from 65 to 67, as “nickel and dime stuff.”

“It’s not insignificant, but it doesn’t preempt a debt crisis,” he said. And it’s certainly not enough to persuade Republicans “to do big-time tax stuff, which would just be bad for growth.”

Ryan acknowledged that this consensus had yet to take hold among elected leaders. Even then, he was looking forward to Nov. 6, 2012, when he predicted that Republicans would win control of the White House and the Senate, and be in a position to “make overtures to centrist Democrats to join us.”

In the end, Ryan was right to be gloomy last year: Every attempt at compromise did fail. Sen. Rob Portman (R-Ohio), an advocate of bipartisanship who served on the doomed supercommittee, declined to fault Ryan’s decision to stay away.

“I spent a lot of time and effort for no result. So it’s hard to say I succeeded,” Portman said.

Still, few observers think the coming election will give either party undisputed control in Washington. Sen. Olympia J. Snowe (R-Maine), a moderate who is retiring this year after a long career of deal making, said Ryan’s uncompromising approach has simply postponed the inevitable and wasted valuable time.

“You put the country in a holding pattern during very tumultuous times when we’re dealing with some of the most consequential economic issues since the Great Depression,” Snowe said. “We’ve been fighting from the last election to the next election. We’ve never stopped. That’s what to me doesn’t make any sense.”