"Saul died because he was unfaithful to the LORD; he did not keep the word of the LORD and even consulted a medium for guidance, and did not inquire of the LORD." (1 Chronicles 10:13-14)
Chronicles compresses the entire reign of Saul into a single chapter: his death on Gilboa, his sons' deaths, the Philistines' display of his body, the men of Jabesh-gilead's retrieval and burial. The Chronicler then gives the theological interpretation that Samuel develops over chapters: Saul died because he was unfaithful to the LORD; he did not keep the word of the LORD and even consulted a medium for guidance, and did not inquire of the LORD. So the LORD put him to death and turned the kingdom over to David son of Jesse. The entire story of Saul in Samuel is summarised in two verses of diagnosis: unfaithfulness, disobedience, consulting the occult, failure to inquire of God. This is what it looks like when a leader forfeits the covenant.
The Catechism draws from the Saul narrative the principle that leadership is a stewardship held in covenant with God: the authority to rule is given on covenant terms, and its forfeiture follows the violation of those terms (CCC 2236).
Brothers and sisters, Saul's downfall is summarised in three failures: unfaithfulness, disobedience, consulting the occult instead of God. Each is a version of the same root: replacing the LORD's authority with your own. Every leader's tenure ultimately rests on whether they inquire of the LORD or consult substitutes. Inquire of the LORD.
Lord God, protect your Church's leaders from the three failures of Saul: unfaithfulness, disobedience, and consulting substitutes instead of you. Give them the David who inquires of the LORD at every step. Through Christ our Lord. Amen.