I'm a bit curious, the US national debt has already reached 40 trillion dollars, and China is one of the major holders of US debt. If the US continues to wage a trade war with China, will it affect the US economy?

These are some things I've heard:

The dollar could weaken If China sells Treasuries and converts the proceeds from dollars into other currencies/assets, that can put downward pressure on the dollar.

Suppose the U.S. runs very large deficits year after year. Eventually investors may say: "If you're going to borrow this much, I want a higher interest rate." That can create a feedback loop: Large deficits → more Treasury issuance