This article seeks to illuminate the long-standing, yet oft-neglected, tradition of “critical Confucianism” by focusing on the Yongjia 永嘉 statecraft thinker Ye Shi’s 葉適 (1150-1223) constitutional vision. Ye Shi’s plans might well be considered ‘constitutional’ as he sought to articulate legitimate ways of limiting state power. Reflecting on the grand social and economic changes we call the Tang-Song transition, Ye Shi redefined the basic assumptions of good government and proposed new ways of framing state society relations for the time. Using the Confucian Classics as the legitimate grounds of his political commentary, Ye Shi criticized the consequences of state-led reforms of the Northern Song (960-1127) era, diagnosed the continuing problems of the Southern Song (1127-1279) imperial state, and proposed his new plans for government. Seen in this light, Ye Shi can be said to exemplify “critical Confucianism,” the long-standing practice of using the Confucian Classics as a legitimizing agent for political claims.