Citizens of the United States generally believe their form of government, a political system based on a written constitution, as something fixed and stable. In reality, it is undergoing a profound change. The idea which constituted its most distinctive feature, and in the belief of many represents America's most valuable contribution to the science of government, is being forgotten. Formed to be "an indestructible Union composed of indestructible states," our dual system is losing its duality. The states are fading out of the picture.