Adam Clarke on 1 Kings 1:12

Save thine own life, and the life of thy son - Nathan took for granted that Adonijah would put both Bath-sheba and Solomon to death as state criminals, if he got established on the throne. O cursed lust of rule! a father will destroy his son, a son depose his father, and a brother murder a brother, in order to obtain a crown! At this time the monarchy of Israel was unsettled; no man knew who was to succeed to the crown, and the minds of the people were as unsettled as the succession. I have examined both systems, and find that, with all its alleged disadvantages, hereditary monarchy has a high balance of evidence in its favor beyond that which is elective, and is every way more safe for the state and more secure for the subject.