When it happens, it's not going to be pretty. If we go to war with China, we're going to have some huge losses initially, beyond's peoples' comprehension. If the nation sees the need to turn back to God right away when that happens, perhaps he might spare us and allow us to find a way to survive and overcome. If not, we're gone.
Ultimately, communism (in this case embodied by China) will have to go to war with free countries. It's a natural existential conflict in that communism and freedom cannot co-exist side-by-side.