What could possibly go wrong?
Gee - I can't think of any reason why you wouldn't install equipment in the CORE of your national communication network from a country that:
- has recently been accused of hacking into businesses all over the world and stealing IP
- has the power to coerce a local company to spy for it while ensuring that that company can't tell anyone about it.
And if you think you can mitigate the risk by inspecting the source code then you're dreaming - for a start try looking at https://en.wikipedia.org/wiki/International_Obfuscated_C_Code_Contest to get an idea of how you can hide stuff if you want. And then the nightmare of checking that *every* piece of kit delivered has the same firware, doesn't have extra hidden ROM, firmware updates are "clean", etc, etc, etc...
BTW - I would be just as suspicious about equipment bought from the USA, except that with the "Five Eyes" agreement they already have access to all our phone conversations anyway!
The bottom line is that if you don't have equipment designed and manufactured in-country you can't really trust it 100%. So you're already stuffed!