it's mostly assembly parts -not just the raw parts like ball bearings."yes you are correct on the tank parts,as well as many weapons systems. It's not a security risk." a #17
There are several security risk.
a) If our indispensable supply of ball-bearings come from Jakarta instead of Peoria, then we'll need to provide military defense to Jakarta in addition to that we already provide to Peoria.
b) We not only would then need to defend the physical plant source. We'd also have to defend the transport path and transport vessels, be they boat or bird.
c) We lose quality control, and expose ourselves to sabotage, getting pebbles instead of precision steel parts.
Also we don't need complete reliance on 1 manufacturer source if strategic conditions change, other sources can be used.
The quality control is built into the bidding process -standards . But obviously we do not test every part for assembly
