Complex sentence: Since Kenyan independence in 1963, Kenyan politics have been characterized by ethnic tensions and rivalry between the larger groups, devolving into ethnic violence in the 2007--2008 Kenyan crisis.
Split into simpler sentences: Since Kenyan independence in 1963, Kenyan politics have been characterized by ethnic tensions and rivalry between the larger groups. This devolved into ethnic violence in the 2007--2008 Kenyan crisis.