Sen. John F. Kerry (Mass.) signed up one of the most prominent and aggressive Democratic consulting firms in Washington to work for his presidential campaign, triggering a serious round of spinning from the campaign of rival Sen. John Edwards (N.C.), who had bid for the services of the same team of strategists.

The not-altogether-clear story of how Bob Shrum and partners Tad Devine and Mike Donilon came to work for Kerry's campaign no doubt holds little interest to the world at large, but it was closely followed and much discussed yesterday inside the often-insular world of political consultants and campaign strategists.

If nothing else, the "Shrum primary," as it was dubbed by "The Note," ABC News's daily political Web report, serves as a metaphor for the intense and growing competition among the Democratic presidential campaigns at a time in the political cycle when relatively small things -- personnel moves, a new poll or a favorable column -- can take on an outsized significance.

By the end of the day, Edwards's advisers were suggesting that they had "won" the Shrum primary and that Kerry's campaign would trade long-term problems for a few days of good press. They also claimed, in a not-so-complimentary way, that the Kerry campaign was beginning to take on the appearance of Al Gore's consultant-laden operation of 2000, a campaign in which Shrum and his partners played a central role. Kerry advisers said the Edwards team risked making enemies for no good reason.

The quiet competition for Shrum's services has been going on for months, but only in the past few weeks have there been offers on the table. Shrum's personal relationship with Kerry dates back three decades, and the senator credits him with helping fend off the stiffest challenge of his career in 1996, when he defeated Massachusetts Gov. William F. Weld (R) after a ferocious campaign.

But Shrum and his firm also acted as the principal strategists for Edwards in his 1998 Senate campaign, the only campaign the North Carolinian had ever run, and Edwards advisers said they believed Shrum would have preferred to work for Edwards in 2004 if the arrangement was right.

Shrum, in a brief telephone interview yesterday, said he and his partners made "an entirely affirmative decision" to work for Kerry in 2004 and declined to discuss his conversations with either campaign. He said he had "great respect for John Edwards," calling his former client "a person of real talent and great promise" for the party. Of Kerry, he said, "He's the best person we can nominate for president and the best person to serve as president."

Edwards's advisers painted Shrum as a potentially disruptive force and said that he and his partners wanted significant control over the campaign's operations and that Edwards "wasn't willing to completely relinquish control of message, campaign budget, press decisions to consultants." The North Carolinian had offered Shrum a more limited role "knowing that it was unlikely that it was going to be accepted," an Edwards adviser said.

Kerry advisers said Shrum's firm will share responsibility for making the campaign's ads with Jim Margolis of the firm Greer, Margolis, Mitchell, Burns & Associates, who handled Kerry's non-competitive reelection campaign last year as preparation for handling the media operation for the presidential campaign.

"Obviously I'm not privy to the conversations that Bob might have had with the Edwards campaign, but his firm was completely comfortable settling into a collaborative arrangement with Jim Margolis and his company," said Kerry campaign manager Jim Jordan.

Democrats not associated with either campaign said Shrum and Jordan have had a prickly relationship in the past, but both men said they are glad to be part of the same team and are eager to work together. Said Shrum, "I think Jim Jordan is doing a superb job."