Originally Posted by DevilDog438

I don't think there is anything in any of the case law reviews that I have read. IMO, it basically boils down to:

1. Prove your "lawful presence" in the United States with some form of definitive proof (see Maryland's definitions here), or
2. Be held, indefinitely, by the "authorities" until your identity and "lawful presence" are validated to their satisfaction, ergo
3. de facto requirement for all US citizens to carry their "lawful presence" documentation at all times when within 100 miles of any US/interational border crossing

Note - I use the term "lawful presence" since that is the artful term that Maryland is using as part of their compliance requirements in advance of the REAL ID deadline.