Rwandan genocide said that "many people were killed in 1994 by both sides making those who carried out the genocide and their enemies morally equivalent". He said that Philpot argued "[t]here was no one-sided conspiracy by armed Hutu forces and militias against a million defenceless Tutsi". In 2009, scholars Christian Davenport of the University of Michigan and Allan C. Stam of Dartmouth asked, "What really happened in Rwanda?" The pair do not question that an anti-Tutsi genocide took place in 1994, but their investigation led them to conclude that "conventional wisdom was only partly correct". They argue that the genocide constituted only
Hutu of Rwandan national unity, but has been criticized as an attempt at historical revisionism. Still others suggest that the two groups are related but not identical, and that differences between them were exacerbated by Europeans, or by a gradual, natural split, as those who owned cattle became known as Tutsi and those who did not became Hutu. Mahmood Mamdani states that the Belgian colonial power designated people as Tutsi or Hutu on the basis of cattle ownership, physical measurements and church records. There is an ongoing debate as to whether the Hutu and Tutsi are really separate groups or not;