WASHINGTON -- Hillary Rodham Clinton's top campaign strategist advised her to cast presidential rival Barack Obama as having questionable "roots to basic American values and culture" and use the theme to counter the image that his background is diverse and multicultural.

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"I cannot imagine America electing a president during a time of war who is not at his center fundamentally American in his thinking and in his values," Mark Penn wrote in a March 2007 memo to Clinton.

Clinton did not take Penn's advice, revealed by a report in the September issue of The Atlantic magazine.

The article said Clinton's campaign for the Democratic presidential nomination went from front-runner status to failure for a number of reasons, from badly managed money to blistering warfare between advisers. Clinton did little to quell the infighting.

Mostly, the disputes were over whether to go negative against Obama, a half-black, Harvard-trained lawyer from a broken home with a gift for soaring rhetoric and big themes.

Penn advised going negative.

"All of these articles about his boyhood in Indonesia and his life in Hawaii are geared towards showing his background is diverse, multicultural and putting that in a new light," Penn is quoted as writing. "Save it for 2050. ... Every speech should contain the line you were born in the middle of America American to the middle class in the middle of the last century. And talk about the basic bargain as about the deeply American values you grew up with, learned as a child and that drive you today. Values of fairness, compassion, responsibility, giving back."

"Let’s explicitly own 'American' in our programs, the speeches and the values. He doesn’t," Penn writes. "Make this a new American Century, the American Strategic Energy Fund. Let’s use our logo to make some flags we can give out. Let’s add flag symbols to the backgrounds."

Penn's memos also contained prescient advice. The memo from March 2007 talked about the importance of a key voting bloc he called "the invisible Americans" -- women and lower -- and middle-class voters.

Those groups helped Clinton beat Obama in key states before she quit the race in June.