Michael Peabody's succinct and insightful history of conscientious objection to military combat is the cover feature for the July-August issue of Liberty magazine. He provides this analysis of how modern democracies motivate people to fight:
Motivating people who enjoy freedom to join a larger fight is more difficult than simply forcing them to do so at the tip of a sword. The loyalty of subjects has been replaced by patriotism and nationalism, and there is an expectation that citizens will take up the fight against the Other.
There is a formula for this rhetoric. The Other has made plans to harm our interests and will carry them out unless these plans are stopped
In 1917 [Theodore] Roosevelt wrote a brief message in a “Pocket Testament” Bible distributed to the troops. Based loosely around Micah 6:8, Roosevelt called on the troops to do justice, love mercy, and walk humbly with God. Under “Do justice,” Roosevelt wrote, “and therefore fight valiantly against the armies of Germany and Turkey, for these nations in this crisis stand for the reign of Moloch and Beelzebub on this earth.”
Superimposing a divine mandate on a military action while demonizing the enemy (in Roosevelt’s case quite literally) can convince millions to pick up arms when they would otherwise feel revulsion toward slaughtering an enemy....
"Watch His Conscience: A Short History Of The Conscientious Objector," Liberty, July-August 2010.