When supplicants answering the Rev. Billy Graham's altar call streamed to the foot of the stage, each would be met by one of the evangelist's helpers. The pairings weren't random.

Graham insisted that young women meet young women. Older men greeted older men. Graham understood that the best way to cement the conversion was to show new believers a reflection of themselves within the church.

Salesmen know that like sells to like. In the early 1960s, a study of insurance agents and policy buyers found that "the more similar the parties" the more likely the salesman would be to make a deal. Men sold best to men. Tall salesmen with college degrees had greatest success with tall, college-educated clients. And sales were highest when the seller and the buyer belonged to the same political party.

It took until 2004 for what was common knowledge among evangelists and insurance peddlers to become the latest gimmick for selling a president. The Bush campaign in 2002 had experimented with different techniques to increase voter turnout, from door-to-door canvassers to the noxious (and utterly ineffective) robo-calls. Their tests found that personal contact with a voter was good, but that an appeal coming from a friend or neighbor worked best. If it was clear to voters that the canvasser came from the same social hive, Bush campaign strategist Matthew Dowd told me, turnout jumped.

The Republican campaign in 2004 recruited neighbors to contact neighbors and it enlisted respected community members to serve as Bush "navigators," local surrogates for the president. The strategy was to reflect voters' beliefs and ways of life back on to themselves, so that the '04 campaign wasn't as much about the re-election of a president and his policies as it was an affirmation of a local way of life.

The Democrats learned their lesson – they used paid workers who obviously were "not from around here" to do their canvassing – and so this year the Obama campaign is recruiting an "army of persuasion" based on the Bush neighbor-to-neighbor model. At training sessions, "Obama Organizing Fellows" are taught to develop short, personal narratives that will explain to their neighbors how they came to support the Democrat.

It may spoil some of the fun for the newly minted Obama fellows to learn that their device is taken directly from the megachurch. Evangelicals have long known that people come to faith most easily through contact with friends and neighbors, and that one of the most powerful ways to draw converts is for believers to "witness" their faith (Acts 1:8) with personal stories of salvation.

Neighbors witnessing to neighbors is a marketing technique suited to Americans, who are increasingly sequestering themselves in communities, churches and clubs with those who share similar ways of life and politics. The tactic isn't to "sell" people something new or different, but to show that the product (a church, a new concoction of PowerBar, a candidate) embodies the community's beliefs and lifestyle.

"The message you've got to send, more than any other message, is that Barack Obama is just like us," Missouri Sen. Claire McCaskill told the Obama fellows, according to the Washington Post. Exactly.

Politicians have been packaging image from the beginning – McKinley sitting on the front porch; Truman speaking from the back of a train; Madison Avenue selling a new Nixon. In the end, however, the message was the same: "Vote for me."

Campaigns today are doing something different. They attempt to manage behavior by creating a social environment that encourages people to vote for themselves. The most important message a campaign has to convey is one of flattery, that the candidate is "just like us."

Self-government, however, is the opposite of self-love. Democracy is about meeting and coming to terms with people who look, talk, believe and think differently from us. Government might work better if that democratic exercise began for voters during the campaign rather than the day after inauguration.

Bill Bishop is author, with Robert G. Cushing, of "The Big Sort: Why the Clustering of Like-Minded America is Tearing Us Apart" (2008). He lives in Austin, Texas.