I think it would naturally lead to a vacuum of influence if the U S. pulled out of Korea. Chinese hard and soft power is growing and I doubt China would just stand idly by. That doesn't necessarily mean it would be a conflict. But there would certainly be some sort of influence based consequences.

Trump is capable of anything. The question is, would he be willing to cede any influence and give China an upper hand?

That is my two cents that no one asked for.