The Japanese attack on Pearl Harbor in December 1941, added patriotic anger to Birch's outrage at Japanese atrocities in China. He was also finding it harder and harder to survive in Shangrao, and his diet made it harder and harder to maintain his health, already weakened by disease. He may also have started to doubt the mission bureaucrats, who soured him on organized religion. On April 13, 1942, he wrote to the American Military Mission in China say that for both patriotic and practical reason he wanted to "jine the Army." He explained that he had been preaching behind Japanese lines for more than a year but was "finding it increasingly hard to do on an empty stomach (no word or funds from home since November)." He wanted to be a chaplain but would cheerfully ""tote' a rifle" or " whatever they tell me to do."
