When Hertzog asked for neutrality towards Nazi Germany during World War II, he was deposed and Smuts became Prime Minister again. During World War II, Smuts was invited to the Imperial War Cabinet again, where he worked closely with Winston Churchill. In 28 May 1941, Smuts became a Field Marshal of the British Army, becoming the first South African to hold that rank. This cooperation with Churchill made Smuts very unpopular with the Afrikaners, which led to his downfall.