This is a flaw in the system. Candidates from 5-eyes partners should be able to get any clearance necessary. I know from experience that Lockheed has a lot of non US nationals working on secret projects which require clearance. During the F-35 program a ton of Brits were involved, both for the avionics components made in the UK, and as test pilots for VTOl (where Brits were preferred given Harrier experience and their acknowledged skill as the best pilots of that type).

I don’t know why Brits, Canadians, kiwis and Aussies can’t get cleared for you guys. They are getting cleared at every level all the time. NSA, CIA, etc.