The process Mosiah set in place did what it was supposed to do. Pahoran was selected to be the Chief Judge, and his brother Pacumeni accepted the result of that legal process. Paanchi did not. As with each of the previous Chief Judges, there was still conflict over the process, and Paanchi and his followers did what Amlici, Amalickiah, and the king-men had done in the previous administrations. He incited people to rebellion.
Paanchi was arrested prior to being able to raise an army, and was executed according to law. His crime would certainly have been treason. His death, however, did not end the political problems. A new problem begins in the next verse.