Within the past decade, the leaders of most Arab monarchies have conducted foreign interventions in Libya, Syria, and Yemen to secure their interests and counter threats. During each intervention, some leaders have changed their strategies, undermining coalition cohesion. Why do members of coalitions change their intervention strategies? The existing literature on interventions mostly focuses on Western states and structural shifts in systemic balance, domestic legislation, or bureaucratic competition. Elizabeth Saunders (2009) departs from these international or state level explanations by assessing the personal threat perceptions of U.S. presidents. In this paper, I adopt this individual level of analysis, focus on the leaders of Arab monarchies, and argue that leaders’ unique material and ideational perceptions of threat and pursuits of opportunities produce distinct intervention strategies. I test this argument by assessing the individual level causes for divergence between Saudi Arabia and the UAE following their intervention into Yemen’s ongoing civil war. Saudi Crown Prince Mohammad bin Salman (MbS) perceived a material threat from the Iranian-backed Houthis and pursued the ideational opportunity for a pliant northern Yemen, committing to a “non-transformative” strategy to restore the ousted President Abdu Rabbu Mansour Hadi to power. Alternatively, Abu Dhabi Crown Prince Mohammad bin Zayed (MbZ) perceived an ideational threat of Sunni Islamist diffusion and pursued the material opportunity for a sovereign southern Yemen. Consequently, the UAE shifted to a “transformative” strategy to reshape Yemeni politics and support a separatist governing entity known as the Southern Transitional Council. This paper aims to demonstrate that the anxieties and ambitions of leaders are essential determinants in both their states’ intervention strategies and the political outcomes of the states into which they intervene.