A sense of shared history is one of the main ways a people come to constitute themselves as a group or nation and to forge a collective identity and a sense of shared destiny. In times of peace and prosperity, this common past may enhance a sense of mutual purpose, instill a pride in public institutions, and fortify a civic patriotism. However, during economic and political crises, some political leaders stir up nationalist sentiments to bolster their increasingly shaky hold on power and legitimacy. Unable to effectively address deepening social and economic problems, they instead vilify an historic enemy, recall past wrongs, and seek to take advantage of the atmosphere of threat and insecurity. If armed conflict breaks out, then historical injuries may be recalled when atrocities are committed against enemy civilians, which are usually justified as reprisals necessary to ensuring the very existence of the group. Although this scenario is neither modern nor new, ethno-nationalist conflicts characterized by extensive civilian casualties became especially frequent after the end of the Cold War.

The politically instrumental use of history during an armed conflict is highly complex and selective. It is not simply a matter of fabricating outright lies, for many of the events that continue to generate a sense of grievance did really happen. As noted in this book, widespread atrocities were indeed committed against Serbs during World War II, and Hutus were cruelly subjugated by Tutsis during the colonial period in Rwanda.