Democrats are in a tight race in Iowa, as Hillary Clinton, Barack Obama and John Edwards all vie for top billing. The candidates haven't been shy about going after each other in speeches and debates, but it's a different story in their campaign ads.
With inspirational music in the background, Clinton's latest ad shows her making a series of broad promises: an end to the war, affordable college and, of course, health care reform.
But the ad doesn't say how Clinton differs from her Democratic opponents on those issues. For example, it doesn't mention her plan to make health insurance mandatory.
Obama's health care proposal relies more on incentives and voluntary participation to achieve universal health care. It's a contentious policy distinction between the two campaigns, but you wouldn't know that from their ads.
"The ads so far — and I don't want to overgeneralize — have been pretty much content-free and information-challenged," says Brooks Jackson, director of factcheck.org, a nonpartisan site that truth-squads the claims made in campaign ads.
But so far, Jackson says, the ads haven't presented many facts to check. Instead, the ads draw style distinctions.
Edwards, for example, has settled firmly into his persona as defender of the little guy. In his campaign ad, he holds a microphone in front of a flag in some intimate venue.
"Do you really believe that if we replace a crowd of corporate Republicans with a crowd of corporate Democrats, anything is going to change?" Edwards asks.
But who's the "corporate Democrat" in this race? The ad doesn't say.
In Barack Obama's ads, he argues that he is a different style of Democrat. Different from whom? He doesn't name names — but he does name a decade:
"I don't want to spend the next year or the next four years refighting the same fights that we had in the 1990s," Obama says in one ad.
"That's pretty, pretty mild stuff compared to what we'll — I'm sure — see before this campaign is over," Jackson says. He says the candidates may be reluctant to draw sharp contrasts with their opponents — for fear that Iowans will think they're going "negative."
"Four years ago, two of the Democratic candidates attacked each other, about this time in the cycle," Jackson said. "Dick Gephardt and Howard Dean ran negative ads against each other, and neither one of them did very well in the Iowa caucuses. So candidates may have that in mind."
But is it possible for candidates to be too polite? Vanderbilt University professor John Geer thinks so.
"Negative ads aren't necessarily fun," says Geer, author of the book In Defense of Negativity. "But it provides a chance to vet ideas, to have a discussion. You need that kind of negativity to stir the pot, to get people to understand that maybe there is a difference between Hillary Clinton's plan and Barack Obama's plan. But you're not going to get that if you only hear the positive side."
This is especially true, Geer says, when you're trying to reach voters who don't necessarily watch the debates or read up on the candidates' plans online.
As Jan. 3 draws closer, the campaigns may still decide it's worth the risk to mix it up with one another in their ads. But in this Christmas season, they'll have to calculate carefully just how far they can go.