What happens when an irresistible force meets an immovable object? When a movement with the force and fervor of standards-based accountability reform hits the massive, highly stable, and reputedly reform-resistant form of the American high school? Something, the song lyrics tell us, has to give. But after more than a decade of focused and forceful reform effort, it is not at all clear what that something will be. Do high school structures give way before the mounting pressure of high stakes tests? Or do standards-based accountability advocates need to throw in the towel, and see this attempt, like so many before it, relegated to the long list of faded reform efforts?