I think that the fact that they use the term president rather than something else establishes the fact that he is, at the very least, an elected official rather than a dictator like Adel.
You mean like President Deling?

I'm pretty sure Laguna is the sole ruler of Esthar and is a benevolent despot. There is absolutely nothing anywhere in the game that suggests that he is an elected official but there is plenty to suggest that his position is permanent.