DES MOINES, Iowa (CNN) -- Sen. Hillary Clinton's rivals sense a little blood in the water after Tuesday night's debate, and they're ready to move in for the kill.
Sen. Hillary Clinton addresses the students of Wellesley College, a women's college, Thursday.
If her rivals want to stop Clinton, they've got to do it in Iowa, where the Democratic presidential race is a dead heat.
David Yepsen of the Des Moines Register thinks her performance in the debate this week hurt her -- and not not primarily because of she is the frontrunner.
"I think what gets her in trouble is waffling, is equivocating, is not being clear." Yepsen said.
Former Sen. John Edwards, who is running third in national polls but is within striking distance of Clinton in Iowa, is releasing a new TV ad in Iowa that draws an obvious contrast.
"It is time for our party, the Democratic party, to show a little backbone, to have a little guts," Edwards says in the ad.
The criticism of Clinton has resonance with Democratic caucus-goers because it reinforces their one big doubt about her: Is she electable?
"Anytime something happens that reinforces Clinton's negatives or bad perceptions about her will raise questions about, well, maybe she can't win in November," Yepsen said.
Clinton is fighting back by releasing her own video on her Web site accusing her opponents -- all men -- of "piling on."
"I seem to be the topic of great conversation and consternation, and that's for a reason," Clinton said.
On Wednesday, when the American Federation of State, County and Municipal Employees, a major government workers' union, endorsed her, the union president said this:
"Some of you may have seen last night's debate," Gerald McEntee said. "Six guys against Hillary. I'd call that a fair fight."
And on Thursday, Clinton made this comment when she visited Wellesley College, her alma mater:
"In so many ways, this all-women's college prepared me to compete in the all-boys club of presidential politics," she told the cheering audience.
Could playing the gender card pay off in Iowa?
"When Sen. Clinton plays that gender defense, I think that is something a lot of women caucus-goers can relate to, they can understand, they've all been in situations where the men are kind of ganging up on them," Yepsen said.