I was able to find some specifics at the Arizona Peace Officer Standards and Training Board website. According to the site, the following are considered valid proof of citizenship:
- A valid Arizona driver license.
- A valid Arizona nonoperating identification license.
- A valid tribal enrollment card or other form of tribal identification.
- If the entity requires proof of legal presence in the United States before issuance, any valid United States federal, state or local government issued identification.
But the real question still remains: what does "reasonable suspicion" entail? Does eating a burrito count? Thankfully, the APOSTB website offers this help:
FACTORS WHICH MAY BE CONSIDERED, AMONG OTHERS, IN DEVELOPING REASONABLE SUSPICION OF UNLAWFUL PRESENCE
- Lack of identification (if otherwise required by law)
- Possession of foreign identification
- Flight and/or preparation for flight
- Engaging in evasive maneuvers, in vehicle, on foot, etc.
- Voluntary statements by the person regarding his or her citizenship or unlawful presence
- Note that if the person is in custody for purposes of Miranda, he or she may not be questioned about immigration status until after the reading and waiver of Miranda rights.
- Foreign vehicle registration
- Counter-surveillance or lookout activity
- In company of other unlawfully present aliens
Location, including for example:
- A place where unlawfully present aliens are known to congregate looking for work
- A location known for human smuggling or known smuggling routes
- Traveling in tandem
- Vehicle is overcrowded or rides heavily
- Passengers in vehicle attempt to hide or avoid detection
- Prior information about the person
- Inability to provide his or her residential address
- Claim of not knowing others in same vehicle or at same location
- Providing inconsistent or illogical information
- Demeanor – for example, unusual or unexplained nervousness, erratic behavior, refusal to make eye contact
- Significant difficulty communicating in English
So, basically, whatever the fuck the officer feels like pulling out of his ass. "Gee, judge, I just sort of thought those shoes looked kinda.. you know... Mexican. And he appeared to be nervous".
This is really scary.