SENDAI — The most important televised debate of the current American presidential campaign was held on the night of Oct. 2, and it featured not the presidential candidates themselves, as one might expect, but rather their vice presidential running mates. The debate was interesting because, while the policy positions of Barack Obama and John McCain are by now well established, the positions and personal qualities of the nominees for the position of vice president are far less well known.

Surprisingly, however, the most interesting moment of this confrontation between Alaska Gov. Sarah Palin and U.S. Sen. Joe Biden occurred just before the debate began. When the candidates strode onto the stage at the University of Washington and shook each other's hands, Palin asked her opponent, "Hey, can I call you Joe?"

This short question reveals a great deal, not only about differences in polite discourse between the United States and many other countries, but also about the underlying politics and strategy of this election-year debate, and about the state of gender relations in the U.S.

Americans seem, especially to outsiders, to crave informality. It is unlikely that two political candidates in any other country, meeting each other for the first time during a televised debate, would instantly expect to address each other by their given names. Sometimes, my friends here in Japan thus assume that Americans are simply not sophisticated or concerned about politeness.

Yet this assumption misunderstands the requirements of polite discourse in the U.S. We should begin by noting that Palin did not merely presume to call her opponent "Joe," but first asked him for permission to do so. She thereby satisfied a basic requirement of politeness, and she also established herself as someone willing to be called by her own given name, that is, as a friendly and approachable person. The first lesson of this brief exchange is not that Americans lack rules for polite discourse, but rather that they follow rules suited to their own, relatively informal, political culture.

This exchange was political, in fact, in more than one respect. The U.S. has always embraced a cultural politics of equality. This is one reason why American politicians, who are nearly always members of a socio-economic elite, are nonetheless obliged to play the electoral game of presenting themselves as middle-class (or even lower middle-class) innocents, uncontaminated by the treacherous sophistication of Washington. They are, in other words, supposed to be "regular Joes."

By invoking this informality, Palin thus played a familiar American political game. Although she has been heavily criticized as lacking sufficient experience for the position to which she has been nominated, she nonetheless revels in presenting herself as an ordinary American "hockey mom." And by signaling her willingness to be informal at the outset of the vice presidential debate, she potentially represents her opponent as someone who might be more formal, more sophisticated, and thus more of an elite political insider. Perhaps Joe Biden is not, after all, a "regular Joe."

Palin's invitation to informality was politically clever, in fact, for a more subtle reason as well. Without overtly appearing to do so, she immediately put her adversary in a very difficult position. The recent success of Hillary Clinton notwithstanding, gender remains an issue in U.S. politics. Women remain underrepresented in American politics, and there is a deep gender gap on many contemporary issues. Despite his far greater experience in policymaking on a national level, therefore, it was important for Biden not to appear condescending or dismissive when referring to Palin.

By implicitly inviting Biden to call her "Sarah," however, Palin put her adversary in a nearly impossible position. To refuse was, in the American context, extremely impolite. And yet, to "take the bait" and to call his opponent "Sarah" would appear to belittle her, given the precarious gender subtext of the debate. Whether this was a strategic gambit by Palin or merely, from her perspective, a happy coincidence is impossible to say.

Wisely, Biden refused to take the bait. Indeed, he scarcely referred to Palin at all during the debate. Clearly, the safest strategy was to attack the head of the Republican ticket, John McCain, and to leave Palin alone. And when he was obliged to refer directly to his opponent, Biden chose the safest route, calling her "Gov. Palin."

Still, inevitably, there was a political price to pay. Palin invoked "Joe six pack" as well as hockey moms. Responding to Biden's own effort to appear more folksy by describing his conversations with ordinary Americans in Katie's Restaurant and Home Depot, Palin implored: "Say it ain't so, Joe, there you go again."

The irony, of course, is that it was precisely Palin who was both more willing and more routinely able to invoke her own casual rapport with ordinary Americans. By almost any measure, Biden displayed far greater sophistication and expertise in public policy than did Palin. But appearances also matter a great deal in American politics, as elsewhere. Palin's opening question to Biden set the stage for a contest of informality at which Palin was at least as effective as her adversary. In this sense, there was nothing especially polite about Palin's rush to get on a first-name basis.

Say it ain't so, Sarah.

Paul Kowert is an associate professor of international relations at Florida International University and a Fulbright visiting lecturer at Tohoku University, where he does research on Japanese and American national identity.