NEW YORK (FORTUNE) - The U.S. economy is the envy of the world - a dynamic, increasingly efficient machine fueled by technology and globalization, among other things. But if the fruits of economic dynamism keep going almost exclusively to the wealthy and well educated, we may be in big trouble.

So say Laura D'Andrea Tyson and Glenn Hubbard, an unlikely pair of economists who paid a recent visit to FORTUNE. Both run business schools now - Tyson is winding down a four-year run as dean of London Business School, and Hubbard is in his second year as dean of Columbia Business School - and they had come to talk about business education (the schools offer a joint executive MBA).

But there was no escaping the fact that Tyson also was a top economic adviser to Bill Clinton and Hubbard was the same to the current President Bush during his first term. Conversation drifted inevitably to economic policy, and mostly stayed there.

An abridged transcript of their talk can be read here, but the short version is this: The Democrat and the Republican agreed wholeheartedly that business schools perform an important function in today's world and somewhat less wholeheartedly (Tyson had some reservations) that the U.S. economy is in great shape. Not too surprisingly, the two disagreed on tax policy. But it was striking how both identified income inequality as perhaps the biggest economic challenge facing the U.S.

"There are a lot of people for whom dynamism and change are not opportunities," said Hubbard. "When I think of the protectionist wave facing the country right now - whether it's China, whether it's offshoring, whether it's the brouhaha over Dubai Ports - a lot of this is because we haven't talked to average people enough about what is going to be in place to buffer them against dynamism."

"But the point is there's nothing in place," responded Tyson. "I agree with you, but what can we say to these people? 'We're going to severely curtail what you can expect from health care for the elderly, so that's going to fall on you and your family. We're going to significantly curtail what you and your family can expect from pensions through Social Security. We're going to severely curtail - this is part of the current budget proposal - funding for grants to go to college."

Tyson argued the Bush administration's tax cuts had only made things worse. "We're dealing with a world in which technology and globalization are driving the returns increasingly to the top 10 percent and even to the top 1 percent," she said. "I don't see why one makes tax policy to aggravate those long-term trends."

Hubbard, who helped devise that tax policy, said cutting income tax rates and taxes on dividends and capital gains had promoted economic growth by reducing the "deadweight loss" due to taxes. "Speaking as an economist, that's where the excess burden of the tax code is."

But he agreed that "pro-efficiency" moves like the Bush tax cuts should have been balanced with what he called "fairness elements," adding, "I just question whether those should be done through a tax code that strikes me as riddled with distortions, as opposed to explicitly helping people."

On the topic of Social Security, one of the major existing "fairness elements," there was an interesting exchange: Tyson criticized President Bush - whom she initially referred to as "your president," prompting Hubbard to point out that "he's all of our president" - for killing any chance of fixing Social Security's long-run funding shortfall by his controversial push for private accounts.

And Hubbard more or less agreed, saying that if Bush had simply proposed fixing Social Security's finances and pushed for his personal retirement accounts outside of Social Security, things would have turned out much better. "We could have won that," he said.

Read more from the discussion with Tyson and Hubbard here.

Plugged in is a daily column by writers of FORTUNE magazine. You can reach today's columnist, Justin Fox, at jfox@fortunemail.com .