Educational reforms fail again and again. One reason for the failure is that educational reform stops just outside the classroom door. During the last 25 years, the dominant educational reform initiatives in the US have operated under the misguided conventional wisdom that the educational system is loosely coupled. With this model in mind, decades of educational reform efforts have focused on tightening the system. Based on empirical results we argue that the educational system is neither loosely or tightly coupled, but bifurcated in that (to borrow a metaphor from geoscience) it is comprised of two tectonic plates. The first plate consists of the state, district and school levels, and the second is the classroom, with a fault line between them. The theory of bifurcated system not only explains why past educational changes have stopped at the classroom door, but also raises the key question of how to bridge the fault line. We propose two principles for school improvement in the bifurcated context. The first principle is to integrate principal and teacher leadership, effectively bridging the fault line in both directions. The second principle is the school renewal process, helping transform the classroom practice by emphasizing implementation "integrity" rather than "fidelity."