Washington ? The can of worms that Howard Dean opened with his ill-conceived effort to identify himself as “the candidate for guys with Confederate flags in their pickup trucks” is not one that can be resealed with the words of regret the former Vermont governor belatedly offered. By inadvertently reopening the deepest wound within the nation, the race issue, Dean hurt himself and did a disservice to his party.

He had said similar things several times in the past, without drawing criticism. But with his big fund-raising lead and his accumulating endorsements, his words are now more consequential. When I was with him in Iowa more than a year ago, the line was somewhat different. Then he was promising his outreach would include “the guys driving pickups with gun racks on the back.” When his opponents started criticizing the stands that had earned Dean an “A” rating from the National Rifle Assn. back in Vermont, he switched the description to the flag decal.

His timing could not have been worse, because Democrats were already undergoing traumatic experiences in and about the South. Bob Graham of Florida had just become the fourth Southern senator to opt out of running for re-election next year, creating open seats in North Carolina, South Carolina, Georgia and Florida, all of which could easily fall to the GOP.

Another of the declared Democratic retirees, Sen. Zell Miller of Georgia, had just published a book and launched on a round of TV and print interviews in which he blamed the party, its leaders and its presidential candidates for taking a “go to hell” attitude toward the South.

And last Tuesday, even as Dean struggled to extricate his foot from his mouth, two more states, Kentucky and Mississippi, elected Republican governors to succeed Democrats — accelerating the Democratic decline in what was once the Solid South.

Throughout the Deep South, as retiring Democratic Sen. Ernest “Fritz” Hollings of South Carolina told me in an interview, the two-party system is increasingly being defined on a racial divide, with African-Americans congregating as Democrats and whites joining the GOP. Hollings said he remains an optimist — believing that the burgeoning federal budget deficits he has decried for so long, plus the exodus of jobs to Mexico and China that has so damaged the economy of his state, will help Democrats retain his seat next year and perhaps over time rebuild their strength. But he and his friend, former state and national Democratic Party Chairman Don Fowler, both acknowledge that it is harder and harder to hold a biracial coalition together — socially or politically.

It was into this troubled environment that Dean, innocently but recklessly, dropped his words. Display of the Confederate flag and its incorporation into state emblems have been at the center of emotional battles in the last decade in state after state. So I asked Merle Black, the Emory University scholar and author on Southern politics, how Dean’s words would be heard by Southerners. “For a lot of African-Americans,” he said, “the fact that Dean used a Confederate symbol is very insulting. That remark can be used effectively against him,” especially in Democratic primaries, where blacks make up a large percentage of the voters.

As for the white voters Dean embraced, Black said, “These are the most conservative voters in the South and the least likely to vote for Dean. I can’t imagine a bumper sticker reading ‘Flaggers for Dean.’ They are the least likely to participate in the Democratic primaries and I doubt they’re really interested in his message. It comes across as saying that ‘Southerners are so dumb they’ve been voting against their own interests, so I’m going to educate them on the error of their ways.’ And what makes it worse, it’s coming from a Vermont Yankee.”

The collapse of the Democratic Party in the South is a huge barrier to its recapture of the White House. Its only presidential winners since John F. Kennedy have been its nominees from Texas, Georgia and Arkansas. Dean is not the first Northern candidate to think he has found a formula for reaching disenchanted Dixie whites. Pat Caddell, the pollster for George McGovern in 1972, argued back then that because George Wallace’s supporters were “alienated from the system,” they could be converted into McGovern voters. But their grievances with the establishment were far different from his — and McGovern lost the entire South.

If Dean has a strategy for the South, he has yet to disclose it. And his campaign blooper just makes the Democratic challenge larger.

David Broder is a columnist for Washington Post Writers Group.