In the Lord of the Rings series, why are the wizards not considered for kingship?

Question

In the Lord of the Rings Series, why are the wizards, like Gandalf, not considered for kingship? I don't mean the sorcerer types like Saruman. I mean the wizards. I am curious because out of all of the characters in the series, Gandalf Stormcrow is the one who exhibits the greatest qualities of leadership, of wisdom, of a divine connection (prophesy when he told which morning he would arrive at Helms Deep), etc., etc., etc. I'm curious to know what opinions others may have on this topic? I am also curious to know whether or not anyone has ever read any revelations explaining such things? It would appear that of all of the characters, Gandalf would be the most qualified to be the king, in my opinion. What do you think and why?

Answer 1

Wizards are usually smart enough to realize they don't want to be a king.  Too much hassle and headaches involved in being a ruler.  

Wizards in Tolkien's eyes were primarily advisers and scientists.

Saruman was a wizard (the leader of Gandalf's order), but he was seduced by the power offered by Sauron.