In the midst of a tense political rebellion, Hushai the Archite must convince Absalom of his loyalty. To remove any suspicion of treason and justify his sudden shift in allegiance from David to Absalom, Hushai presents a calculated and diplomatic set of arguments. He offers a second main reason for presenting himself at the new royal court [רד״ק, ביאור שטיינזלץ]. By rhetorically asking who he should now serve, Hushai defends his actions from both practical and moral standpoints.
On a practical level, David has been removed from power and is expected to face exile, death, or complete political irrelevance [ביאור שטיינזלץ]. Morally, Hushai argues that transferring his loyalty to Absalom is not an act of betrayal against David. He is not defecting to a rival dynasty, such as the family of Saul, but is simply continuing to serve the son of the king [מצודת דוד]. He assures Absalom that he will fulfill his new role with the exact same dedication he previously gave to his father.
Adding a deep psychological layer to his plea, Hushai suggests that once David is defeated and accepts his new reality, even he would prefer that his close friend serves his son rather than a stranger. Furthermore, Hushai's history as a deeply loyal servant and friend to David is meant to inspire a strong sense of trust and affection in Absalom [מלבי״ם]. Ultimately, these persuasive arguments succeed. Absalom accepts the reasoning and welcomes Hushai into his close circle of advisors [ביאור שטיינזלץ].