Three Black, Two White

A riddle for you:

A dying king decided to appoint his successor from one of three wise men, and to decide between them he placed them in a room, one each on three chairs, all facing the same direction such that the man on the chair at the back could see the two occupants before him, as the man in the middle could see the occupant before him and the man in the front could see nobody. No man could see the top of his own head.

The king brought out five hats - three black, two white. He randomly placed three of these on the heads of the wise men. He told them they had half an hour, without moving and in silence, to work out what colour hat they sported. At the end of the half hour if any man was able to identify their hat correctly, and with sound reason, he would be appointed the next king. If not, all three would be executed.

The king returned when the time had expired, and at last the man at the front stood up, saying "I have a black hat, and I refuse to explain my reasoning." All three were duly executed. So, the question is: What the hell did he do that for?

Oh, and also, I have decided I am highly amused, to the point of obsession, with the new Optimus Prime Voice Changer Helmet, available RRP £30 from all good stores. I intend, however, never to procure one.

Here, then, is another riddle:

A dying king, in choosing a successor of his three wisest men, places three chairs in a row, all facing one direction. He seats one wise man in each, and brings into the room five Optimus Prime Voice Changer Helmets, three functional, two broken. The helmets are assigned randomly, and each hat is "operated" once. But, the questions are: Who gets to be king? Who gets to be Optimus Prime? Are the broken helmets irreparable?