Iraq has become a hotbed of conflict as a result of regional, national, and international trends and competitions. The political-sectarian identity crisis that was concealed during Saddam's reign has become the primary challenge of the Iraqi political society after the fall of his regime. A sociological investigation of these identities, especially among Kurds, Shiites, and Sunnis, demonstrates that the political open space after Saddam increased their tendency towards “sub-sectarianism” to meet their demands and create identities of resistance against the government and the Iraqi national identity. Iraq's political identities are also concerned that political elites, as in the past, seek to establish an identity to dominate others. As a result, supranational identities have grown stronger, and post-Saddam Iraq has experienced more crises and political instability. These supranational identities have ultimately caused and added to the fragility of the Iraqi political system. Therefore, this descriptive-analytical study aimed to investigate the role of political identities in the political instability of Iraq in the post-Saddam era. The main research question was as follows: What was the role of political identities emerging in the post-Saddam era in the political instability of Iraq? Results showed that the emergence of resistance identities as a result of sub-sectarianism tendencies against the national government will lead to “political instability” in the future of Iraq.