From Jan 12 to 14, 2026, the Fifth Plenary Session of the 20th CPC Central Commission for Discipline Inspection is being held. Looking back at the "cave-dwelling conversation" in Yan'an, a US youth reflects on a question that still resonates today: when a ruling party grows larger and governs for longer, who supervises the supervisors? In China's answer, people's oversight and self-reform point to the same core. In practice, that means drawing clear boundaries, keeping power under institutional constraints, and maintaining the courage to correct mistakes.