First: federal employees with security clearance
Next: all federal employees & all foreign nationals in the US
Next: all those working in "sensitive" industries
Next: all those working in "economically-vital" industries.
See where this is going?
Sorry, we're already there.
All healthcare workers that can access financial or 'personal' data (which means everyone north of the janitor) are now subjected to background checks that have to be redone every six years. Next up - constant monitoring to ensure we don't steal Grandma's SSN. Interestingly, the way the rules read, they're not much worried about us stealing medical information, just financial. One has to have one's priorities.