THOUGH HE REMAINS coy about his plans, US Senator John Kerry has been getting plenty of press coverage for his tentative steps toward a presidential run in 2004. His August 5 appearance at a fundraiser for the mayor of Manchester, New Hampshire — at which he responded to applause by joking, " I accept the nomination! " — was covered by CNN and noted in the national press. Later that week, in his Beacon Hill home, Kerry hosted a fundraiser for the governor of Iowa. This act of hospitality prompted Boston Globe columnist Scot Lehigh to demand that Kerry " acknowledge the obvious " and admit that he’s making plans beyond next year’s Senate re-election campaign. And Salon.com’s Jake Tapper noted a few weeks ago that Kerry has also made recent speeches in Colorado, Georgia, and Texas, concluding that " to watch Kerry now is to watch a man who appears to be sounding out to himself his own reasons for running. "

If Kerry does run for president, he’ll be the fourth Massachusetts politician in a quarter-century to be a serious contender for the Democratic nomination, following Ted Kennedy, Michael Dukakis, and Paul Tsongas. But he’ll be on the wrong side of a deep geographical split in the party. Put him against a white Southerner — if not former vice-president Al Gore, then most likely North Carolina senator John Edwards — and his chances may well evaporate.

A Southern candidate for the Democratic nomination starts out with a geographical advantage that extends far beyond the 11 states of the Confederacy. In presidential primaries, the constituency for such contenders includes border states such as Kentucky, Missouri, and Oklahoma. It also includes the underbellies of Illinois, Indiana, and Ohio, which are all geographically closer to Louisville than to the Great Lakes. It has outposts in African-American neighborhoods in Chicago, Detroit, and other major Frost Belt cities, where many voters responded to Jimmy Carter’s and Bill Clinton’s histories of working with civil-rights leaders. And it includes the hinterlands in many Northern states, where voters may resent their lack of influence in gubernatorial elections and the winner-take-all Electoral College system. Since Democratic convention delegates are awarded on a proportionate basis, it can be profitable for Southern candidates to mine these mostly rural areas. For example, there’s Coos County, on New Hampshire’s Canadian border, which Bill Clinton easily carried in 1992 even as Paul Tsongas won that state’s primary. Or take Pennsylvania, which the New York Times last year described as " Philadelphia and Pittsburgh with Alabama in the middle. " In 1980, Ted Kennedy narrowly defeated Jimmy Carter statewide, thanks to his strength in the cities, but Carter was able to walk away with more convention delegates because of his appeal in the more culturally conservative parts of Pennsylvania. (Unfortunately for Kennedy, he was equally weak in both the urban and rural parts of the South.)

All these pieces can add up to a majority coalition in the Democratic primaries. When there’s been at least one white Southerner among the major Democratic candidates, this coalition has been amazingly stable — ranging from 48.8 to 51.8 percent of the total primary vote from 1976 through 1992. Northern and Western candidates, by contrast, seem to top out with percentages in the low 40s (see " The Southern Coalition " ). Last year, of course, Tennessee’s Al Gore got almost 80 percent of the primary vote against the hapless Bill Bradley — a New Jersey resident who futilely tried to emphasize that he grew up in Missouri. In a Boston Globe story on Kerry’s recent visit to New Hampshire, a supporter is quoted as saying, " He’s the heir apparent to Bill Bradley’s voters. " I’d ask to be written out of that will.