China gov also said that McArthur want to use atom bomb, but was denied by USA gov. So even McArthur's threat is true, we could prepare for the war but it was not necessary to send our army before we were attacked. If USA gov really want to declare war on China, it could accept Jiang's advise and help Guo Ming Dang to attack China from FuJiang too. It was better to attack China from the South and the North at same time. But it did not happen. So USA did not prepare to fight with China at that time.