Michelle Obama's eyes flicker tentatively even as she offers a trained smile. As her campaign plane arcs over the Flathead Range in Montana, she is asked to consider her complicated public image. Conservative columnists accuse her of being unpatriotic and say she simmers with undigested racial anger. A blogger who supported Senator Hillary Rodham Clinton circulates unfounded claims that Obama gave an accusatory speech in her church about the sins of "whitey." Obama shakes her head. "You are amazed sometimes at how deep the lies can be," she says in an interview. Referring to a character in a 1970s sitcom,...