The election may depend upon it: How to instruct the average American voter to discern the difference between a poisonous lie and a truth based on evidence. A fine June 30 Washington Post story written by Eli Saslow vividly and painfully illustrates the point.

The writer tells the tale of Jim Peterman, a 74-year-old retiree of Findlay, Ohio, torn between what he sees on television about Barack Obama and what he hears from his neighbors. The neighbors are passing on rumors including that Obama is a Muslim and is unpatriotic, while television ads portray him as a Christian family man who loves his country. “It’s like you’re hearing about two men with nothing in common,” Peterman says. “It makes it impossible to figure out what’s true, or what you can believe.”

The Obama campaign has established a “Fight the Smears” Web site, but it may be fighting an uphill battle because the rot goes deeper than we can know. Susan Jacoby, a former Washington Post reporter,has written a book called “the Age of American Unreason” in which she traces the many ways in which citizens of this country dwell in a world of willed ignorance: not understanding basic history, democratic principles, scientific thinking, rules of evidence, even the difference between fantasy and reality. How can we make up for that abysmal deficit in an election season, when it is especially vital that voters base their decisions on fact, not fiction?

Many years ago when I was associate dean at the Columbia University journalism school, the dean – former managing editor of Newsweek, Osborn Elliott – and I taught a class for undergraduates called “Critical Evaluation of the News.” The idea was to challenge young people to weigh the evidence before them, even when it is published in established media like The New York Times. Perhaps a course like that should be taught in high schools around the country because without knowing how to evaluate information critically the average citizen is not only flying blind, but a patsy for malicious rumor-mongers.

I would also like to second a proposal by Eboo Patel, a Washington Post blogger and director of an interfaith youth group. He suggests that John McCain should stand up and speak out against the lies, misrepresentations, and prejudices being propagated about his opponent. After all, Obama regularly praises McCain for his service to the country. This kind of straight talk could elevate the dialogue between the candidates to where they are being judged by their true character, their beliefs and proposals, rather than an underground trail of hate-filled smears.