by David Epstein
I have a new theorem about negative campaigning in primaries (which is to say it is mine (Money Python reference)). Take a primary campaign in which one candidate is more extremist relative to the national distribution of voters (e.g., Obama), and the other more moderate (e.g., Clinton). Then negative attacks by the more extremist candidate are less damaging to the party in the national election than negative attacks by the moderate.
Why? Because the attacks by the extremist (taking the Obama-Clinton example) are of the form "Your positions are too far right." So Obama says that Clinton is too hawkish on the war. This is an attack that makes sense in a Democratic primary, but it's certainly not one that McCain will repeat in the general election; if anything, it helps her in November.
But Hillary attacks Obama by saying that he's too dovish, not experienced enough for the tough foreign policy challenges that he would face as president (this is the real message of the 3AM telephone call ad). This is an attack that McCain would certainly repeat and that damages Obama as a general election candidate.
I note this asymmetry not to make value judgments, but just because it's interesting and I hadn't heard it mentioned before. It does clarify a few elements of the current situation, though. To start with, it helps remind us that in a way Obama has been running a negative campaign from the very beginning, saying that Clinton was wrong on Iraq and he was right. In fact, I see his entire policy strategy as copying Clinton on every other major issue, so that these are a draw, and winning on Iraq. (There's also the old politics vs. Yes We Can dimension, but let's not go there now.) Obama hasn't received much flack for these attacks, partly because they bolster Hillary's image as a hawk, which she will certainly want to project in the national election once she's the nominee.
On the other hand, Hillary has to walk a finer line when she attacks Obama, because she's making many of the same points that any Republican opponent would. So she gets accused of disregarding the party's overall interests, sometimes fairly (she absolutely should not be saying that McCain is a better leader than Obama; that's heresy), sometimes not. But the rules are different for her, to some degree because she's Hillary and a Clinton, and to some degree because of the geometry of the situation.