Why did Thomas Becket revoke his assent to the Constitutions of Clarendon?

Thomas Becket revoked his assent to the Constitutions of Clarendon primarily because he believed the articles contravened canon law and the spiritual independence of the church.12

While Becket initially promised to observe the 16 articles under pressure from King Henry II, he quickly repudiated his oath. The most contentious issue was the provision regarding "criminous clerks," which allowed for the secular punishment of priests charged with serious felonies. Becket argued that a guilty cleric should not be punished twice for the same fault—maintaining that once a man was degraded or punished by an ecclesiastical court, he should not be subject to further secular penalties.12

Beyond this, the Constitutions restricted the church's power to excommunicate royal officials, limited judicial appeals to Rome, and granted the king control over episcopal elections and the revenues of vacant sees. Becket’s refusal to accept these terms led to his six-year exile and eventual martyrdom.12