Depends "national security" is much more than defence industries back when I worked BT the team leaders on some projects where getting positively vetted for SC

Depends "national security" is much more than defence industries back when I worked BT the team leaders on some projects where getting positively vetted for SC clearance - That's top secret in US terms. Arguably now the FANGS are now CNI - which is going to suck if your on a H1B or Green Card.