Transshipment is the elephant in the room here - smaller components made in PRC, then shipped to wherever as Raw Materials (tm), and then put in a "friendly nation" box and sold as safe.
DoD's DMEA and DLA CD programs, plus GIDEP reporting, capture confirmed cases . . but not the miss rate. On the occasion they do bust open a jet (or god forbid a missile) and look at all the bits with a microscope, it can be scary.
[1] They like to avoid the more precise "criminal fraud"