Here is some really interesting stuff from the Border Patrol's own official Inspector's Field Manual. The BP tried to keep this from being released, but eventually a lawyer got it through FOIA. VERY interesting read as it's actually a bit more restrictive than even the case law. You can read the manual in PDF format here:
Border Patrol Inspector's Field Manual (2008)
"18.6(E) Checkpoints:
The Border Patrol conducts two types of inland traffic-checking operations: checkpoints and roving patrols. Border Patrol agents can make routine vehicle stops without any suspicion to inquire into citizenship and immigration status at a reasonably located permanent or temporary checkpoint provided the checkpoint is used for the purpose of determining citizenship of those who pass through it, and not for the general search for those persons or the vehicle. Inquiries must be brief and limited to the immigration status of the occupants of the vehicle. The only permissible search is a “plain view” inspection to ascertain whether there are any concealed illegal aliens."
- Customs & Border Protection, Inspector's Field Manual (2008)
"18.7(B) Reasonable Suspicion:
Before an inspector may constitutionally detain a person (non-entry related case), the inspector must have reasonable suspicion that the person is an alien and is illegally in the United States. This higher degree of suspicion arises generally in questioning persons encountered in and around the port who are awaiting persons referred to secondary. This suspicion is based on questioning of alienage alone and also involves specific articulable facts, such as particular characteristics or circumstances which the inspector can describe in words."
- Customs & Border Protection, Inspector's Field Manual (2008)
And this is particularly interesting in light of this military officer's video. Apparently if he was entering the country (and not just driving on a highway in the USA), he would not be required to show a passport to enter the country and is exempted. And that's assuming he was a non-citizen military enlisted man, not an officer who must be a citizen.
"Chapter 11 - [Persons Exempt From Immigration Inspection When Entering the United States]:
Alien members of the U.S. military and NATO forces from member nations signatory to Article III of the Status of Forces Agreement entering under official orders are exempt the controls of the INA, pursuant to 8 CFR 235.1(c), including the requirement to present a passport and visa [See also section 284 of the INA.]. Such persons returning to the U.S. after a temporary trip are also eligible for this exemption without presenting any official orders."
- Customs & Border Protection, Inspector's Field Manual (2008)