Eller has a particular interest in ethnic conflict. He observes how ethnicity has become central to social discourse and social competition. He analyses the concepts and definitions of ethnicity and ethnic groups, seeking further clarification by considering these alongside notions of state and nationalism. He distinguishes between past as tradition or 'cultural' past and the past as history and as myth, notiing how the ethnic past serves as a resource. He observes that "a simple tallying of the cultural distinctions between groups, or a faithful and 'objective' recounting of their histories, will not get us closer to their ethnicity. Rather, it is critical to understand how groups marshal, interpret, and use their cultures and histories - or their memories or perceptions of their cultures and histories - to define themselves and press their claims, in confrontational and eventually violent ways."