The 2009 TIME 100

During the worst economic crisis since the 1930s, Sheila Bair has been the little guy's protector in chief. Guaranteeing the savings of bank customers is the main job of the chair of the Federal Deposit Insurance Corporation. Bair did that while the FDIC handled 25 bank failures in 2008. To boost trust, she also upped the guarantee from $100,000 to $250,000. "No customer has ever lost a penny of insured deposits," she says.

Bair's unusual clout, though, derives from the breadth of her command and her guts in staking new ground. An early Cassandra about the dangers of subprime loans, she incensed Treasury officials last fall by pushing aggressively for a massive mortgage-refinancing program. "She will stick to her guns even if it's not the popular view," says personal-finance expert (and fellow TIME 100 honoree) Suze Orman.

Bair, 55, is the rare Republican who has not only survived in the Obama Administration but gained power. The government has enacted many of the mortgage-modification proposals she championed. And the FDIC now has oversight of public-private funds that are being created to buy troubled bank assets to crank up lending again. A lawyer who hails from tiny Independence, Kans., Bair believes that fiscal responsibility begins at home. She's written two children's books on the subject. In Rock, Brock and the Savings Shock, about twin boys who get money from their grandpa, the lesson is clear: "You just have to stop spending all your money and save."

Sellers is an editor-at-large at Fortune