You either meet ICAO standards (cat 1) or you do not (cat 2).
Where this comes into play is whether or not you're servicing the US at the time you're placed in category 2. If you're not severing the US, you won't be any time soon.
If you're serving the US as a Cat 1, and placed into Cat 2, you can continue to service, with some restrictions....
I think I'm close ;-)