A Spanish anthropologist working with a team of archaeologists at Machaquila, south of Tikal, has concluded that the decline of the Maya civilization began when their kings stopped being immortal in the eyes of their subjects.

Andres Ciudad's theory that the Maya at some point understood there was no sense in working themselves to death building pharaonic edifices and temples destined for the burial of kings who had no "heavenly privileges" weakens theories that attribute the death of this civilization to tribal warfare or prolonged drought*, and has also led to confirmation that the Mayas did not build an empire as such, but rather forged a series of decentralized states in which a noble caste governed together with the kings.

Report here

* For the drought theory, see Climate and the Collapse of Maya Civilization, an article from American Scientist that explores the evidence for a series of multi-year droughts contributing to the collapse of Classic Maya civilization.