Mosiah declares that they would use the voice of the people to establish judges who would judge “according to the laws which have been given you by our fathers, which are correct, and which were given them by the hand of the Lord.” Thus, Jehovah would continue to be their lawgiver, and the judges would be in place to govern in accord with established law.
It is important to understand that this is not a declaration that Mosiah established voting and elections. We will see that judges will also become hereditary positions, and the voice of the people never functions as a vote. We remember that the voice of the people was a mechanism that functioned under the monarchy as well, so there isn’t a major change. The difference is that there would no longer be a king who was presumed to speak with and for Jehovah directly in the way laws were enacted. The judges would tend to work within the laws which the fathers received from Jehovah.