Why doesn't Prince William go to war? instead they choose Prince Harry.?

Question

and i know prince Harry decline go to war in 2007.

Answer 1

There's actually rules against it.  William can't go into combat: he's too high up in the succession.  Harry did NOT decline to go to war.  He wanted to go, but it was determined by his superiors that he was too high profile and would end up further endangering his men.

Answer 2

William wanted to go, but they said the enemy would make him too high of a priority target, and that would endanger his peers.  He is heir to the throne.

Answer 3

Because they don't want the future king to die first.

Answer 4

William in first in line for to the throne.