For example, in "" (2000), Jeffrey Herbst explains that "domestic security threats, of the type African countries face so often, may force the state to increase revenue; however, civil conflicts result in fragmentation and considerable hostility among different segments of the population", undermining the state's ability to rally the population's support for the "national project" (2000: 126). In a later article, Herbst argues that war in Europe lead to strong states and that without war African states will remain weak. In Europe, external threats allowed states to tax, increase taxation, and forge a national identity. Additionally, the states that were invaded and taken over (such as Poland-Lithuania or Ireland) by stronger countries were militarily and politically weak. African states are poor, have weak governments, and are fragmented on ethnic or regional lines. According to theory, these weak African states should be susceptible to external threats, but this is not the case. In Africa, Herbst notes, there are rarely conflicts between states, and if there are, war does not threaten the existence of the state. For example, in the 1979 Uganda-Tanzania War, Tanzania invaded Uganda to overthrow Idi Amin, but after the Tanzanians had removed Amin, they left the country. Although African states do not experience widespread interstate war, Herbst argues they need it to reform the tax structure and to build a national identity. Herbst concludes that war in Africa is likely to occur when African leaders realize that their economic reforms and efforts to build a national identity do not work and in desperation will start wars to build the states that their countries need. James Robinson disagrees with Herbst in the grade of influence of war on state-building, stating that European colonization and European influences in the continent impacted more deeply the creation of institutions, and therefore, states in Africa.