Only in the past 30 years has the interpretation of the Anasazi decline incorporated the latest archaeological findings. Needless to say, these findings are unpopular. Drought was, perhaps, the final straw that moved all of them out of the region. The bones, however, tell the sad story of the wars, the disease (mostly tuberculosis), cannibalism and genocide that afflicted the peoples of the area. This interpretation is not popular, but it is increasingly accepted by researchers in the area. The progressive movement and decline of settlements in the Four Corners is well-documented and dated by tree ring, pollen and other data.
Not until 1850 did an American building reach the size of one constructed by the Anasazi before their troubles. They abandoned that dwelling site because of reasons already stated- overpopulation and destruction of their immediate environment. Religious schism and warfare soon developed. Later settlements, and an abortive attempt to resettle the core areas, failed as a drought cycle intervened.

About warfare and disease:
White, 1992, Prehistoric Cannibalism at Mancos, Princeton Univ. Press; White, D. L., 1991, Black Mesa Anasazi Health, Reconstructing Life from Patterns of Death and Disease, S. Illinois University; J. Haas, 1990, Warfare and Evolution of Tribal Politics in the Prehistoric Southwest, in the Anthropology of War, Cambridge; and also his Stress and Warfare Among the Kayenta Anasazi of the Thirteenth Century, Field Museum, 1993; S. LeBlanc, Prehistoric Warfare in the American Southwest, Univ. Utah, etc.

Anasazi was a word applied by the early archaeologists and anthropologists; I believe it was a Navajo word that they adopted. Hum-a-Hah is a current word (what language?); what the Anasazi called themselves is unknown. Laguna was established about 1700 by a small group from Acoma, (plus some others?) and in 1700 numbered only 330.