Dan Quayle, the vice president under George H.W. Bush and a master of malapropisms, once said "One word sums up … the responsibility of any vice-president, and that one word is 'to be prepared.'" Quayle's embarrassing gaffe, neither his first nor his last, can teach us two things about being a presidential running-mate. First, you need to be prepared. Second, you cannot be embarrassing.

In Thursday's debate, both Governor Sarah Palin and Senator Joe Biden seemed prepared to give intelligent responses to most topics. Perhaps more importantly, neither of them said anything particularly cringe-worthy.

Even though both candidates seem to have the most fundamental qualifications to be vice-president, the two candidates showcased differing styles that will compete for voters' affection. They subtly highlighted geographical differences and serious philosophical disputes.

Palin's pitch

Governor Palin focused on her connections to the American heartland and conservative philosophy. The governor was born in Idaho and has spent most of her life in Alaska. Palin talked about how her experience as Alaska's governor makes her particularly qualified to deal with energy related issues.

In a telling exchange, she even demeaned Senator Biden and other "Eastern" politicians as hampering the expansion of oil drilling in other regions of the country. She also used religious language extensively and colloquially. Palin was playing to one segment of the middle class: a group of predominantly Protestant, socially conservative Midwesterners that she is emulating and praising to help win the election.

Biden targets working-class voters

Palin stays casual, Biden gets personal

The language and speech patterns used by the candidates also emphasized the differences between them. Palin spoke with a noticeable accent. This accent, an interesting and distinctive blend that sounds both Midwestern and Alaskan, may help her connect with voters who see it as a mark of her solidarity with the electorate. Palin also favored informality in her speaking style. She dropped the "g"'s off of the end of her words and her now famous catchphrase, "you betcha," appeared consistently. Governor Palin also used specific language to emphasize with the middle class. She referred to the everyday American male as "Joe Six-Pack" and talked about economic hardships though the quotidian experience of "soccer moms."

The unforgettable "hockey moms" of her convention speech also made an appearance in Palin's talking points. By mentioning them, Palin is probably trying to boost her Nordic credentials and her "tough-mother-figure" persona.

In contrast, Biden spoke with almost no accent and instead used personal examples to connect with average Americans. He talked about families that could not fill up their gas tanks, and his son's military service. Perhaps most touchingly, Biden recounted his first wife's death in a car accident and his subsequent struggles as a single parent.

Biden, like Palin, was making a specific appeal to a segment of the American population. He did not try to play up his folksiness, and seemed to represent best the middle class of the East and West Coasts of the United States.

In conclusion, both Biden and Palin appeared to be competent and informed in the vice-presidential debate, but their styles could not have been more different. Partially informed by their backgrounds and greatly influenced by the audience they were trying to court, the two candidates used specific rhetoric and stories to convey their message. All that remains to be seen is which narrative will best capture the hearts and minds of Americans come November.