Prices would rise significantly and it would create a very large black market. There would be supply issues for more than a decade. The US does half a trillion dollars worth of importing from China. Every major US retailer is designed around imports from China. Most of that is relatively low priced consumer goods. Where do you plan to buy decently priced microwaves, by the millions, that aren't made in China? That doesn't exist, it would take years to bring that production on-line. The same is true of television sets. Hell, just about anything you can name that is mass consumer oriented. The disruption to supply would destroy most US retailers instantly. Walmart and Amazon, both suddenly lacking 3/4 of their inventory, would go bankrupt in a matter of months. Walmart would have to fire upwards of two million low income workers that have no possible replacement jobs.
It would harm the bottom 50% in the US the most. That's enough reason to look at other options first.
I don't see the ramifications playing out remotely like that.
There'd be a diplomatic tit-for-tat leading up to sanctions, they wouldn't just be turned on at 00:00 tomorrow. So there'd be perhaps a year. Sanctions tend to start with specific items and scale up. So it's a process, with a timeline, over perhaps 2 - 10 years.
Plenty of time for significnt amounts of trade to move to india, Vietnam and the other developing economies.
China holds quite a bit of US currency, the risk of offensive use of this has been assessed by the US as not too severe, but 3.2 trillion is a lot.
It might be better used hurting US interests abroad rather than devaluing the $US.
It would harm the bottom 50% in the US the most. That's enough reason to look at other options first.