It's been said that every society has two aristocracies. The members of the aristocracy of mind produce ideas, and pass along knowledge. The members of the aristocracy of money produce products and manage organizations. In our society these two groups happen to be engaged in a bitter conflict about everything from S.U.V.'s to presidents. You can't understand the current bitter political polarization without appreciating how it is inflamed or even driven by the civil war within the educated class.

The percentage of voters with college degrees has doubled in the past 30 years. As the educated class has grown, it has segmented. The economy has produced a large class of affluent knowledge workers — teachers, lawyers, architects, academics, journalists, therapists, decorators and so on — who live and vote differently than their equally well-educated but more business-oriented peers.

Political scientists now find it useful to distinguish between professionals and managers. Professionals, mostly these knowledge workers, tend to vote for Democrats. Over the last four presidential elections professionals have supported the Democratic candidate by an average of 52 percent to 40, according to Ruy Teixeira and John Judis, authors of "The Emerging Democratic Majority."

Managers, who tend to work for corporations, brokerage houses, real estate firms and banks, tend to vote Republican. Thanks to their numbers, George Bush still won the overall college-educated vote.

This year the Democrats will nominate the perfect embodiment of an educated-class professional. John Kerry graduated from law school and plays classical guitar. President Bush, however, went to business school and drives a pickup around his ranch. So we can watch the conflict between these two rival elites play itself out in almost crystalline form.

This educated-class rivalry has muddied the role of economics in shaping the political landscape. Republicans still have an advantage the higher you go up the income scale, but the correlation between income and voting patterns is weaker. There is, for example, this large class of affluent professionals who are solidly Democratic. DataQuick Information Systems recently put out a list of 100 ZIP code areas where the median home price was above $500,000. By my count, at least 90 of these places — from the Upper West Side to Santa Monica — elect liberal Democrats.

Instead, the contest between these elite groups is often about culture, values and, importantly, leadership skills. What sorts of people should run this country? Which virtues are most important for a leader?

Knowledge-class types are more likely to value leaders who possess what may be called university skills: the ability to read and digest large amounts of information and discuss their way through to a nuanced solution. Democratic administrations tend to value self-expression over self-discipline. Democratic candidates — from Clinton to Kerry — often run late.

Managers are more likely to value leaders whom they see as simple, straight-talking men and women of faith. They prize leaders who are good at managing people, not just ideas. They are more likely to distrust those who seem overly intellectual or narcissistically self-reflective.

Republican administrations tend to be tightly organized and calm, in a corporate sort of way, and place a higher value on loyalty and formality. George Bush says he doesn't read the papers. That's a direct assault on the knowledge class and something no Democrat would say.

Many people bitterly resent it when members of the other group hold power. Members of the knowledge class tend to think that Republican leaders are simple-minded, uncultured morons. Members of the business class tend to think that Democratic leaders are decadent elitists. In other words, along with the policy and cultural differences that divide the groups, there are disagreements on these crucial questions: Which talents should we admire most? Which path to wisdom is right? Which sort of person deserves the highest status?

That's the kind of stuff that really gets people riled up.

This contest between rival elites certainly doesn't explain everything about our politics. But with their overwhelming cultural and financial power, these elite groups do frame the choices the rest of the country must face. If not for the civil war within the educated class, this country would be far less polarized.