A change of royal power is accompanied by all sorts of uncertainty. Laman's son felt no obligation to keep covenants his father had made with Zeniff (Mosiah 9:6). His political plan was no doubt popular among the Nephite haters. Thus he had them prepare for war. The children of Israel found themselves in a similar situation when the Pharaoh who knew Joseph died and passed the kingdom on to his son:
'Now there arose up a new king over Egypt, which knew not Joseph.
And he said unto his people, Behold, the people of the children of Israel are more and mightier than we:
Come on, let us deal wisely with them; lest they multiply, and it come to pass, that, when there falleth out any war, they join also unto our enemies, and fight against us, and so get them up out of the land.
Therefore they did set over them taskmasters to afflict them with their burdens.' (Ex 1:8-11)