If we eliminated our worst teachers, Bill says it would have a tremendous impact on America's worldwide standing. "If you do that," he says, "then we go from being basically at the bottom of the rich countries to being back at the top."

However, the current system isn't set up to allow such simple firings because tenure guarantees teachers their jobs for life—sometimes after just two years, say Michelle and Davis.

"It's automatic," Davis says. "You show up for two years, and you get tenure.

In Waiting For "Superman", Michelle tries to break apart the notion of tenure with a new proposal that would allow Washington, D.C., teachers to choose to give up their tenure in exchange for double their salary—up to $140,000. At the time, the union refused to put it to a vote.

See what Randi Weingarten, president of the American Federation of Teachers, has to say about this controversial film.