Gideon chooses not to kill Noah, even though that was clearly his intention. Why is the presence of the Lamanites enough to change his mind? Was there some reason he could not first kill Noah, then meet the Lamanite threat? If the scenario I have hypothesized is correct, dispatching Noah would not have been either quick or easy. In fact, he may well have been able to kill Gideon, which would have left the defense of the city in great danger without Gideon to lead his men. Given the choice between a protracted delay while he killed the king, or the immediate ability to rally forces to meet a much larger challenge, Gideon chose the more pressing immediate threat of the Lamanites. This decision further suggests that Gideon was fairly firmly in control of the government, so that he could rally the military forces without worrying about Noah attempting to wrest back control.