> The United States Supreme Court ruled that Border Patrol agents may stop a vehicle at fixed checkpoints for brief questioning of its occupants even if there is no reason to believe that the particular vehicle contains illegal people. The Court further held that Border Patrol agents "have wide discretion" to refer motorists selectively to a secondary inspection area for additional brief questioning.
I think SCOTUS was wrong to permit those, too, but they're significantly different. Registration and DWI checkpoints rely on something outwardly visible/demonstrable; a sticker or signs of intoxication.
There's no outward sign of citizenship, nor are citizens required to carry proof of it.
https://en.wikipedia.org/wiki/United_States_Border_Patrol_in...
> The United States Supreme Court ruled that Border Patrol agents may stop a vehicle at fixed checkpoints for brief questioning of its occupants even if there is no reason to believe that the particular vehicle contains illegal people. The Court further held that Border Patrol agents "have wide discretion" to refer motorists selectively to a secondary inspection area for additional brief questioning.