After 2003, Iraq became an arena of strategic competition between the Islamic Republic of Iran and the United States, but the emergence of widespread protest movements in October 2019, accompanied by explicit anti-Iranian and anti-American slogans, challenged the equations of this competition and confronted both actors with an endogenous identity crisis. This study aims to comparatively examine the diplomatic and operational behavior of Iran and the United States in the face of protest movements and identity developments in Iraq between 2019 and 2023, and seeks to answer the fundamental question: What are the similarities and differences in the approaches of the two countries in managing this crisis and what theoretical frameworks have each used to protect their interests? This study, using a qualitative method and a comparative-analytical approach, and using a theoretical framework combining "Steven Walt's Balance of Threat Theory" and "constructivist approach", has analyzed the military, political, diplomatic, and identity dimensions of the behavior of the two countries. The research findings show that: Under the influence of the maximum pressure strategy and based on the perception of the threat posed by Iranian influence, the United States focused its response on military deterrence and hardware measures, including drone attacks, the response to the embassy attack, and the assassination of General Soleimani. However, these measures led to a decrease in Iranian influence and paved the way for an increase in anti-American nationalist sentiments and a strengthening of the position of Iranian proxy groups.