This study analyzed the illicit tools used by Yemen’s political regime to maintain power and their impact on political legitimacy. Using a case study methodology and a historical approach, it examined the regime’s experience from Yemeni unification to 2011 and explored the legitimacy crisis amid Yemen's conflict. The study found that over three decades, the regime’s illicit strategies eroded state legitimacy, reduced political awareness, and empowered traditional forces over civil parties, resulting in fragile legitimacy. Key tools included exploiting social divisions, constitutional amendments, proliferating opposition parties, institutionalizing corruption, controlling the military, and leveraging anti-terrorism rhetoric, enabling the regime to retain power while undermining political legitimacy.