The American continent was populated relatively recently: the man only appeared at the end of the Paleolithic. Between 50,000 and 12,000 BC reached the first people to the New World, and soon the whole American continent was populated by people. From linguistic and archaeological studies indicate that the Mayans already around 2000 BC. one must have been recognizable culture. The ethnogenesis of the Mayas took place most likely in the Sierra de los Cuchumatanes in western Guatemala. Archaeology has shown that the Maya already from that time began to put down his buildings for ceremonial purposes. From this early time is not quite clear where the boundaries lie between the actual Maya and their neighbors, the Olmecs. The two cultures seem to have influenced each other. Eventually, the Olmec culture faded after its influence on the Yucatán Peninsula to have the current Guatemala expanded.
I think it's because they didn't want it to be so easy for someone to step in and issue new decrees randomly. Everyone would need to agree, given that America runs on a democracy.
