Dunbar is one of four county chairs—essential figures in any Iowa campaign—who have backed out since being identified as Edwards chairs in a June press release. Ernie Schiller of Lee County says he’s now undecided, Frank Best of Louisa County has switched to Obama and Jody Ewing is supporting Bill Richardson.

Iowa voters are notoriously fickle and pick their candidates late in the game. But county chairs are not just any voters. They are the key grass-roots figures who help deliver votes on caucus night, now less than two months away. Four years ago, news of defections hurt Dick Gephardt over the summer and Howard Dean just before caucus night.

The Edwards campaign says the defectors are just a handful of people among more than 4,000 supporters listed in press releases. “We have rolled out more public supporters than any other campaign,” says Dan Leistikow, Edwards’s spokesman in Iowa. “We feel very good about the strength of our organization.” The Edwards campaign also identified three supporters it had poached from other campaigns. When contacted by NEWSWEEK, one denied having switched; the other two were initially Obama backers who switched after their unions endorsed Edwards.

The county chairs are not the only losses for Team Edwards. Several other backers, all named in prior press releases, have also defected. Gary Anhalt was named as an “education professional for Edwards” in September, but says he’s now uncommitted. Barton Rule was a former Tom Vilsack supporter who endorsed Edwards, but says he’s now backing Clinton, as is Jay Kleaveland, a rural chair for Edwards in Clayton County.

Polling in Iowa is imprecise, but most show Edwards losing ground of late. No poll has put him in front since August. In the last month he’s been either tied with Obama for second place, or several points behind him in third. Campaigns can always replace individual supporters—but reversing a trend is much harder.