I'm not saying there's no possible conflict of interest here or that China wouldn't try something or that we should continue to use Shenzhen Fastprint for circuit boards to go in our super premium fancy stealth doodads.
I'm saying this is stupid and a non-issue and people should calm down.
If you know very little about someone, just examining their laundry will tell you quite a bit about them. So 'effective' is really relative.
And, I'd argue that just having their hands on a physical component gives them the ability to introduce purposeful exotic flaws which they can exploit, or just ensure failure sometime in the future yet aren't detectable by standard quality control methods. Kinda like 'zero-day' code flaws that are kept in ones back pocket until needed.
China is far less capable, and nobody else is even close to being able to reach national self-sufficiency without going back to a very primitive meager existence.