conscientious objector 
noun
A person who for reasons of conscience objects to serving in the armed forces.She put several political leaders who didn't agree with her in jail years before politicians started swarming to cells for reasons other than being conscientious objectors....
- In the past, sedition charges have been brought against unionists, conscientious objectors, and those advocating unpopular or ‘unpatriotic’ political causes.
- She was a pacifist and a conscientious objector and served the sentence after refusing to pay the £2 fine imposed on her.
Derivatives
conscientious objection
- But the absolute pacifism and conscientious objection of early Christianity foundered when Constantine converted to Christianity.
- This isn't a sphere where conscientious objections are tolerated, either among doctors or patients.
- The ironic thing is that today, even in the secular forum, conscientious objection is not only accepted but also respected by civil authorities who allow people to do things such as decline military service on moral grounds.