https://en.wikipedia.org/wiki/Tariff_in_United_States_histor...
In the event that a country lacks a comparative advantage sufficient to balance trade and maintain local employment and economic growth; Then some degree of trade restriction is useful to ensure both stability and future growth. At 15-20% local unemployment, losing the perceived future growth engine(s) of the economy to foreign competition would not be politically acceptable to a majority of Americans.
How this plays out in the digital age is interesting. Tariffs are largely ineffective due to the nature of services. China has successfully grown a domestic tech industry from 0 - FANG equivalent by blocking all foreign competitors. It will be interesting if the EU seeks a similar strategy to grow its tech sector.
The EU is indeed slowly taking that direction: https://www.ft.com/content/7738fdd8-e0c3-4090-8cc9-7d4b53ff3...
Presidents are allowed wide latitude in National Security matters.
I expect the sanctioning of WeChat will happen eventually.
The right response would be something like a US GDPR, allowing US persons to opt out of surveillance foreign and domestic. But that would upset the Silicon Valley gravy train, so instead we get a ham-fisted response that deflects concern onto a tiny slice of the overall problem.
Edit: that’s what I thought (and I agree with you), but I wanted to make sure since some other commenters sensed the ambiguity.