If there is a war, the products will be banned. Total embargo. You don't continue trade with your enemy. We didn't continue trade with Japan after Pearl Harbor (and, in fact, were imposing restrictions well before that...which is part of what prompted them to attack us). It just doesn't happen.

Yes, it would hurt us, also. Hardly "cripple" us. There would be a spike in inflation as people scrambled to provide alternative sources for products, which almost certainly would be produced with more expensive labor. China will be hurt more than us, but we would feel it. China's economy is already not doing well. Ours has more resilience than theirs, at least at the present time.

What would more likely be a problem is that a lot of that trade would go through the South China Sea, which would be the battle zone. Some of it might be able to go around Mindanao to avoid at least some of the risks of sailing through a war zone. Others might have to go the other way across the Indian Ocean and around Africa (Suez isn't an option right now).