The Chicago talk-show host and billionaire trendsetter has launched many a product and book onto the bestseller list with her endorsement—and Democratic strategists say there’s no reason she couldn’t do the same for a political candidate.

Obama’s October appearance on her show helped move his book, The Audacity of Hope, from number 14 on the Amazon.com bestseller list to number 1. She also helped him bump John Grisham out of the top spot on the New York Times bestseller list.

If Winfrey threw her weight behind Obama—the two are close, and Obama is her senator—it could help deliver a key demographic to the Illinois wunderkind.

For politicians, Oprah has a dream audience: The many overworked mothers who watch Oprah are among the most important swing voting blocs; they are expensive to target and hard to persuade.

For her part, Winfrey has made Obama promise that if he runs, he’ll announce for the presidency on her show.