Exit polls have shown that the contest between Hillary Clinton and Barack Obama has produced deep divisions among Democratic constituencies. It looks something like tribal warfare. Whites have voted, if you average the results from the states, 53 percent to 39 percent for Clinton; blacks, 80 percent to 17 percent for Obama; Latinos, 58 percent to 39 percent for Clinton; Asians, in California (the one primary state where they're numerous enough to gauge), 71 percent to 25 percent for Clinton.

The differences in voting by the young, overwhelmingly for Obama, and the elderly, overwhelmingly for Clinton, are as large as any I can remember in either a primary or general election. Upscale voters are heavily for Obama; downscale voters are heavily for Clinton.

As the contest has continued, increasing percentages of Clinton and Obama voters say they wouldn't vote for the other candidate against John McCain.

But the exit polls don't show another tribal division, one that emerges when you examine the election returns by county and congressional district. In state after state -- from New Hampshire and Michigan to Texas and Ohio -- Obama runs unusually strongly in counties with large universities. Academics -- and I include here those who choose to live in university towns as well as those actually in or teaching school -- seem to find Obama particularly appealing.

Also, Obama runs unusually well in many state capitals -- Concord, Lansing, Tallahassee, Atlanta, Nashville, Santa Fe, Dover, Jefferson City, Sacramento, Trenton, Madison, Columbus, Austin -- which of course have unusual concentrations of public employees (and in some cases big universities, as well).

Clinton's highest percentages come in counties with large numbers of Latinos and what I call Jacksonians. You can see the latter in counties in what is loosely called Appalachia -- southwest Virginia, southern Ohio, the north end of Georgia, non-metropolitan Tennessee, northern Alabama, northeast Mississippi, all of Arkansas, southern Missouri, eastern Oklahoma, east and central Texas.

These are lands that were settled by the colonial era immigrants from northern England, Scotland and northern Ireland and their descendants, who thronged down the Appalachian chain and then, like their heroes Andrew Jackson and Sam Houston, kept going southwest.

Clinton's strong performance among Jacksonians may reflect her positive appeal (it certainly does in Arkansas), but it also seems to reflect a distaste for Obama. Buchanan County, Va., which borders the yet-to-vote states of West Virginia and Kentucky, voted 90 percent for Clinton and 9 percent for Obama.

What's behind these sharp divisions? You could sum it up by saying that Jacksonians are fighters and academics (and public employees) are not. Jacksonians fought fierce battles against Indians as they moved southwest; they have always made up a disproportionate share of the American military (and were on both sides in the Civil War).

As historian David Hackett Fischer writes in "Albion's Seed," they believe in natural liberty -- I'll leave you alone if you'll leave me alone, but if you attack my family or my country, I'll kill you. Academics are, to say the least, lightly represented in the American military, and in economic terms they tend to compete with the military for public dollars. They seek honor for the work of peace as fiercely as Jacksonians seek honor for the feats of war.

Barack Obama notes again and again on the campaign trail that he spoke out against going to war in 2002 and calls for withdrawal from Iraq, though on terms that he leaves hazy and vague. This suits academics -- and many journalists with similar mindsets -- just fine. It's in line with their portrayal of our soldiers as victims, not heroes, and their portrayal as heroes the academics (Obama used to teach at the University of Chicago Law School) who spoke out against the war.

Hillary Clinton from the beginning of the year has portrayed herself consistently as a fighter, on the campaign trail if not in Iraq, and has done best when she kept fighting while her campaign seemed on the brink of collapse. Her story about being under fire in Bosnia turned out to be untrue, but it is true that we have seen her rebound from adversity multiple times over the last 15 years.

Polling suggests that the Democratic nominee may not be able to count on the losing candidate's tribes in November. Academics and young people and blacks may not turn out in extraordinary numbers for Clinton, as they have for Obama, and the upscale may prefer McCain to a tax increase.

Similarly, Jacksonians, the elderly, the downscale and Latinos may prefer the very Jacksonian McCain to Obama. All of which should worry the super-delegates who must determine who wins the Democrats' tribal war.