A debate Monday night in Myrtle Beach, to the extent that it was about issues at all, was contested in the arena of tax rebates, health care mandates and stimulus plans. It was the culmination in this primary of a shift from the more glamorous issues of war and peace and to the dry, kitchen-table topics of domestic economic policy.

And that means that policy wonks, econo-nerds with last names like Goolsbee and Sperling, have supplanted the campaigns’ high-profile foreign policy firmament as the key advisers upon whom the hopes of the candidates hinge, waging complex proxy wars through the candidates and offering grist for reporters, pundits and bloggers, whose reaction to each complex rollout these days starts arriving well within the hour.

“It’s good that the issues are returning to the forefront after being overshadowed by Iraq and similar issues for so many years,” said Gene Sperling, Hillary Clinton’s chief economic adviser and Bill Clinton’s former national economic adviser.

Loquacious when on topic but generally low key, Mr. Sperling, 49, said the increased emphasis on economic issues meant that “a candidate or policy maker could make news on the domestic economy,” especially because there is “a greater receptivity in the media.”

Mr. Sperling, of course, is not new to the national limelight. A firm believer in promoting traditionally progressive values while unapologetically making the case for private sector growth, market incentives, and the inevitability of globalization (he wrote a book called The Pro-Growth Progressive: An Economic Strategy for Shared Prosperity), Mr. Sperling has been on the national political scene for more than 15 years.

As such, he had a word of warning to his counterparts, who perhaps were letting their new relevance to the national debate in the year of a presidential election go to their heads.

“Policy advisers who think major shifts in national news coverage are about them don’t last long, nor should they,” he said.

Don’t tell that to Austan Goolsbee, Mr. Obama’s chief economic adviser and wunderkind economist, who since age 25 has been a professor at the University of Chicago. Mr. Goolsbee, adoringly known as “GSB” on economic blogs, wrote early and presciently about how the Internet would affect pricing, and has since written on a broad array of topics for publications including The New York Times, Slate and Business Week. The Financial Times called the spindly and demonstrative 38-year-old one of the “Gurus of the Future,” and even conservatives like George Will have written of him approvingly.

(Mr. Goolsbee, a former national debate finalist at Yale—and a serious contender in high school at Milton Academy, where, in 1987, he took second place in the National Forensic League championship tournament for his delivery of a speech he wrote himself called “Rite of Passage”—has the reputation as something of an eccentric. “The one thing you don’t want to do is share an office with Goolsbee, as I do at the campaign,” said David Axelrod, the Obama campaign’s chief adviser. “Because you never get anything done. He’s always regaling you with stories.”)

Mr. Goolsbee is palpably enjoying his time as Mr. Obama’s economic sage.

“It couldn’t be a bigger difference from my day job,” said Mr. Goolsbee.

A college pal of Obama foreign policy adviser Samantha Power, with whom he knocked on doors in the days before the Iowa caucuses, Mr. Goolsbee argues that the campaign is something of an economics hothouse.

“It’s funny,” he said. “I don’t know what it says about the candidates, but the three of us come from different worlds. Most of the Clinton team are kind of the wise political hands from the 90’s. Leo [Hindrey, John Edwards’ chief economic adviser] is more of a businessman and a friend and supporter of Senator Edwards. And I’m an academic and an economist, and the people that we have tended to loop in are Ph.D. economist types.”

That is a characterization to which Mr. Sperling takes strong exception.

“No,” he said when told of Mr. Goolsbee’s depiction. “Senator Clinton likes to take in a broad base of top academic views but also to integrate that with pragmatic analysis of what policies work in the real world and whether they’re capable of being passed.”

This is just one of the many things the two leading economists, whose generational differences reflect those of their candidates, disagree on.

“There is more pressure in general on the campaign, and I think certainly there was a time very early in the summer when most of the campaigns were at a very high level; there weren’t a lot of specifics going around.”

As the two advisors see it, there are major differences between the two plans.

They differ, famously, on their health care plans, where Mrs. Clinton mandates universal insurance coverage and Mr. Obama does not.

Mr. Goolsbee characterized the Obama tax plan as emphasizing simplicity, offering up to $1,000 tax rebates and using a default enrollment to get working people to use savings plans. He said Mr. Obama’s stimulus plan was superior to Mrs. Clinton’s because it quickly put money into the hands of consumers through unemployment insurance, checks to Social Security recipients, mortgage relief and tax rebates. (Critics such as Paul Krugman of The New York Times have said that the Obama plan is not a true stimulus plan because it only moves up the tax cuts Mr. Obama had already called for, but offered no significant new relief.)

Mr. Sperling described Mrs. Clinton’s tax plan as more progressive, because it offered similar tax rebates, but also a 100 percent match on workers’ savings. As for Mr. Goolsbee’s criticisms of Mrs. Clinton’s stimulus plan as too onerous and slow to be effective, Mr. Sperling said the targeted programs Mrs. Clinton called for—to help struggling Americans pay their heating bills and weatherize their houses—would be quickly enforced because many of the programs already exist and because governors would be eager to get billions in federal funding around the country.

And he argued that her mortgage relief plan, to freeze foreclosures for 90 days and freeze housing rates for five years—was the boldest way to stabilize an economy that Mrs. Clinton said on Tuesday morning was at risk of falling into “a deep and long recession.”

Those policy differences have been echoed by Mr. Obama and Mrs. Clinton throughout the campaign, but during Monday night’s debate the candidates expressed those differences in a heated manner usually reserved for surrogates.

“It is absolutely critical right now to give a stimulus to the economy,” Mr. Obama said at one point. “And Senator Clinton mentioned tax rebates. That wasn’t the original focus of her plan. I think recently she has caught up with what I had originally said, which is we’ve got to get taxes into the—tax cuts into the pockets of hard-working Americans right away.”

Mrs. Clinton later sought to clarify the point, arguing tha
t her original plan was “$70 billion in spending with a $40 billion contingency that was part of the original plan, in order to have that money available for tax rebates” and accused Mr. Obama of not paying for his proposals.

“What she said wasn’t true,” said Mr. Obama. We account for every single dollar that we propose.”

It was that exchange that led to all the night’s negative nastiness—and the next day’s.

In a speech the morning after, Mr. Obama said, “She thought it could wait until things got worse. Five days later, the economy didn’t really change, but the politics apparently did, because she changed her plan to look just like mine.”

And so on.

This level of scrutiny and instant-comparison has become the norm, beginning, really, with the release of the Democratic candidates’ health care plans late last yearCK. Paul Krugman of The New York Times—who now blogs—and an army of Internet-based commentators combed through them and were declaring their judgments within a mini-news-cycle.

“Part of that is making sure that we have reached out to bloggers or groups of bloggers when you unveil a plan,” said Mr. Sperling, who said that in the case of the health care plan one had to go not only to the traditional top reporters and columnists but also the top bloggers, so even if they were putting something out in two hours, they had been given time and help to better understand it.

In the “spin room” after the debate in Myrtle Beach, top advisers to both campaigns acknowledged the primacy of pocketbook issues—and began reciting from their meticulous, carefully devised economic talking points.

“I think economic issues are paramount,” said Mark Penn, Mrs. Clinton’s chief pollster. “She’s got a full plan, in terms of stimulus, that involves not just stimulus and rebates but also dealing with the mortgage crisis, foreclose freeze, and interest rate freeze, and also has a long-term job creation [plan] that could start right away in terms of green jobs.”

Moments later, just a few yards away, Mr. Axelrod said, “There were some distinctions on how we approach some long-term economic challenges. She says she is going to be the steady, experienced hand at the tiller, but you know, as he said tonight, it’s not enough to be ready on day one—you also have to be right on day one.”