The opening of diplomatic relations between the United States and Cuba, a momentous change in Latin American regional affairs, raises the question of whether and how the United States will be able to use its new position vis-à-vis Cuba to support political reform and opening there. A potentially critical, yet still largely unexplored, dimension of this question is whether the major Latin American powers can play a bridging role, taking advantage of their efforts in recent years to include Cuba in different regional forums and organizations to provide a pro-reform push at this important new moment. Their willingness and ability to do so is a test of their broader commitment to supporting democracy and human rights throughout the hemisphere.