For your consideration ...
In order for one to legally work in the U.S., they must fill out a Form I-9 and present the supporting documentation.
As to U.S. law, of the GCA 18 U.S.C. 922, I was already aware.
That is a process. Which the "Act" does not address at all. The "Act" mentions no Federal Law/s, Federal Statute, that would specify how an alien is legally authorized to work in the United States that a prospective employer would reference to assist in determining the "lawful status" of an individual. That, in and if itself, leaves the door wide open for abuse.
Now, if only, by Federal Law,
US Citizens and lawful permanent residents can process and own a firearm, how would it be possible, according to Illinois, that an alien person would be able to hold a law enforcement position using their terminology "legally authorized to work in the United States under federal law" which doesn't address the legal possession of a firearm? As it stand, they contraindicate themselves: Legally allow to work in the US, is far different from having to be a US Citizen or lawful permanent resident that can process and own a firearm.
What they do mention is this: "and is authorized under federal law to obtain, carry, or purchase or otherwise possess a firearm,". That statement only applies to US Citizens and lawful permanent residents via the GCA. They mention DACA, however that law doesn't authorize those alien individuals to "obtain, carry, or purchase or otherwise possess a firearm". The law as written is extremely contradictory.
What it boils down to is this, as the "Act" reads, the only people that can apply for the positions the "Act" is written for, is US Citizens and lawful permanent residents. They mention "legally authorized to work in the United States" (as a ruse). Many aliens that are legally authorized to work in the United States, are not US Citizens nor lawful permanent residents. So on that basis, the entire "Act" is pointless and does nothing new.