With the exception of a certain silver-haired former president, Elizabeth Edwards may carry more clout than any other political spouse in the 2008 race for the White House. Despite her charismatic public appearance, some in the campaign are worried about the potential downside of her increased role.

Sources with ties to the campaign tell Radar that some staffers are increasingly concerned by what they perceive as Mrs. Edwards's loose-cannon behavior, citing in particular her heated on-air debate with conservative pundit Ann Coulter on Hardball with Chris Matthews last week. While defending her husband earned the struggling campaign its fair share of publicity and helped them reach second quarter fundraising goals, not everybody involved with the campaign was impressed. "[Taking on Coulter] creates a perception problem," a source tells Radar. "[Senator Edwards] still has to overcome the 'Wimp Factor' in a lot of circles. The last thing he needs is the appearance that his wife is fighting his battles for him."

Mrs. Edwards's tough-talk is nothing new. According to a recent Men's Vogue article, she had to be talked out of launching a blistering attack against John Kerry during the 2004 primaries, after Kerry made a joke about Edwards being in diapers when Kerry was fighting in Vietnam. In a separate 2004 incident, she confronted Dick Cheney on-stage about an inaccuracy in one of his answers used during a debate with her husband. The article also claims Mrs. Edwards is an equal terror in the campaign office, dismissing staffers she views as disloyal.

Perhaps of more concern to the staff is Mrs. Edwards's newfound influence over the actual direction of the campaign. A New York Times profile says Elizabeth advocated hiring Joe Trippi, Howard Dean's prickly former campaign manager. Those close to the campaign see the move as a signal that the '08 campaign will move in a more progressive direction than in 2004. "Trippi is Elizabeth's guy," one source says. "He's going to pull the campaign in the direction she wants."

Still, despite her ever-sharpening tongue and behind-the-scenes maneuvers, the campaign still views Elizabeth as one of their most powerful weapons. "The bottom line is that people still like her. She's an asset," says one aide. "Hopefully, she'll stay that way."