In 1943, James Girouard, a Canadian, filed a petition for naturalization. When asked if he’d “take up arms in defense of this country,” he said, “No (Non-cabatant) Seventh Day Adventist.” He did say, however, that he’d serve in the army as a noncombatant. A lower court admitted him to citizenship, but on appeal the decision was reversed. This case went up to the Supreme Court, and on March 4, 1946, oral argument took place. On April 22, 1946, Justice William O. Douglas delivered the opinion for the Court and stated, “The oath required of aliens does not in terms require that they promise to bear arms. Nor has Congress expressly made any such finding a prerequisite to citizenship.” He further explained that, [o]ne may adhere to what he deems to be his obligation to God and yet assume all military risks to secure victory. The effort of war is indivisible, and those whose religious scruples prevent them from killing are no less patriots than those whose special traits or handicaps result in their assignment to duties far behind the fighting front. Each is making the utmost contribution according to his capacity. The fact that his role may be limited by religious convictions, rather than by physical characteristics, has no necessary bearing on his attachment to his country or on his willingness to support and defend it to his utmost.”
Take a look at an article published in Conscientious Objector in May 1946, about this case at http://bit.ly/2mXaFvi.