Full Idea
There is a certain symmetry here. The permissibility of disobeying a command to fight in an unjust war suggests the permissibility of disobeying a command not to fight in a just war.
Gist of Idea
If soldiers can't refuse to fight in unjust wars, can they choose to fight in just wars?
Source
Jeff McMahan (Killing in War [2009], 2.7)
Book Reference
McMahan,Jeff: 'Killing in War' [OUP 2009], p.92
A Reaction
The argument considered here is that since we could never allow soldiers to choose to fight in their own wars, we similarly cannot let them opt out of the official wars. Implying obedience is absolute. Soldiers don't get to 'choose' anything!